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/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
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   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
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   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
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   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */


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#ifdef USE_PRAGMA_IMPLEMENTATION
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#pragma implementation				// gcc: Class implementation
#endif
#include "mysql_priv.h"
#include <m_ctype.h>
#include "my_dir.h"
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#include "sp_rcontext.h"
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#include "sp_head.h"
#include "sql_trigger.h"
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#include "sql_select.h"
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static void mark_as_dependent(THD *thd,
			      SELECT_LEX *last, SELECT_LEX *current,
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			      Item_ident *item);

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const String my_null_string("NULL", 4, default_charset_info);

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/****************************************************************************/

/* Hybrid_type_traits {_real} */

void Hybrid_type_traits::fix_length_and_dec(Item *item, Item *arg) const
{
  item->decimals= NOT_FIXED_DEC;
  item->max_length= item->float_length(arg->decimals);
}

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static const Hybrid_type_traits real_traits_instance;
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const Hybrid_type_traits *Hybrid_type_traits::instance()
{
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  return &real_traits_instance;
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}


my_decimal *
Hybrid_type_traits::val_decimal(Hybrid_type *val, my_decimal *to) const
{
  double2my_decimal(E_DEC_FATAL_ERROR, val->real, val->dec_buf);
  return val->dec_buf;
}


String *
Hybrid_type_traits::val_str(Hybrid_type *val, String *to, uint8 decimals) const
{
  to->set(val->real, decimals, &my_charset_bin);
  return to;
}

/* Hybrid_type_traits_decimal */
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static const Hybrid_type_traits_decimal decimal_traits_instance;
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const Hybrid_type_traits_decimal *Hybrid_type_traits_decimal::instance()
{
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  return &decimal_traits_instance;
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}


void
Hybrid_type_traits_decimal::fix_length_and_dec(Item *item, Item *arg) const
{
  item->decimals= arg->decimals;
  item->max_length= min(arg->max_length + DECIMAL_LONGLONG_DIGITS,
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                        DECIMAL_MAX_STR_LENGTH);
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}


void Hybrid_type_traits_decimal::set_zero(Hybrid_type *val) const
{
  my_decimal_set_zero(&val->dec_buf[0]);
  val->used_dec_buf_no= 0;
}


void Hybrid_type_traits_decimal::add(Hybrid_type *val, Field *f) const
{
  my_decimal_add(E_DEC_FATAL_ERROR,
                 &val->dec_buf[val->used_dec_buf_no ^ 1],
                 &val->dec_buf[val->used_dec_buf_no],
                 f->val_decimal(&val->dec_buf[2]));
  val->used_dec_buf_no^= 1;
}


void Hybrid_type_traits_decimal::div(Hybrid_type *val, ulonglong u) const
{
  int2my_decimal(E_DEC_FATAL_ERROR, u, TRUE, &val->dec_buf[2]);
  /* XXX: what is '4' for scale? */
  my_decimal_div(E_DEC_FATAL_ERROR,
                 &val->dec_buf[val->used_dec_buf_no ^ 1],
                 &val->dec_buf[val->used_dec_buf_no],
                 &val->dec_buf[2], 4);
  val->used_dec_buf_no^= 1;
}


longlong
Hybrid_type_traits_decimal::val_int(Hybrid_type *val, bool unsigned_flag) const
{
  longlong result;
  my_decimal2int(E_DEC_FATAL_ERROR, &val->dec_buf[val->used_dec_buf_no],
                 unsigned_flag, &result);
  return result;
}


double
Hybrid_type_traits_decimal::val_real(Hybrid_type *val) const
{
  my_decimal2double(E_DEC_FATAL_ERROR, &val->dec_buf[val->used_dec_buf_no],
                    &val->real);
  return val->real;
}


String *
Hybrid_type_traits_decimal::val_str(Hybrid_type *val, String *to,
                                    uint8 decimals) const
{
  my_decimal_round(E_DEC_FATAL_ERROR, &val->dec_buf[val->used_dec_buf_no],
                   decimals, FALSE, &val->dec_buf[2]);
  my_decimal2string(E_DEC_FATAL_ERROR, &val->dec_buf[2], 0, 0, 0, to);
  return to;
}

/* Hybrid_type_traits_integer */
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static const Hybrid_type_traits_integer integer_traits_instance;
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const Hybrid_type_traits_integer *Hybrid_type_traits_integer::instance()
{
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  return &integer_traits_instance;
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}

void
Hybrid_type_traits_integer::fix_length_and_dec(Item *item, Item *arg) const
{
  item->decimals= 0;
  item->max_length= 21;
  item->unsigned_flag= 0;
}

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/*****************************************************************************
** Item functions
*****************************************************************************/

/* Init all special items */

void item_init(void)
{
  item_user_lock_init();
}

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/*
TODO: make this functions class dependent
*/
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bool Item::val_bool()
{
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  switch(result_type()) {
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  case INT_RESULT:
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    return val_int() != 0;
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  case DECIMAL_RESULT:
  {
    my_decimal decimal_value;
    my_decimal *val= val_decimal(&decimal_value);
    if (val)
      return !my_decimal_is_zero(val);
    return 0;
  }
  case REAL_RESULT:
  case STRING_RESULT:
    return val_real() != 0.0;
  case ROW_RESULT:
  default:
    DBUG_ASSERT(0);
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    return 0;                                   // Wrong (but safe)
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  }
}


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String *Item::val_string_from_real(String *str)
{
  double nr= val_real();
  if (null_value)
    return 0;					/* purecov: inspected */
  str->set(nr,decimals, &my_charset_bin);
  return str;
}


String *Item::val_string_from_int(String *str)
{
  longlong nr= val_int();
  if (null_value)
    return 0;
  if (unsigned_flag)
    str->set((ulonglong) nr, &my_charset_bin);
  else
    str->set(nr, &my_charset_bin);
  return str;
}


String *Item::val_string_from_decimal(String *str)
{
  my_decimal dec_buf, *dec= val_decimal(&dec_buf);
  if (null_value)
    return 0;
  my_decimal_round(E_DEC_FATAL_ERROR, dec, decimals, FALSE, &dec_buf);
  my_decimal2string(E_DEC_FATAL_ERROR, &dec_buf, 0, 0, 0, str);
  return str;
}


my_decimal *Item::val_decimal_from_real(my_decimal *decimal_value)
{
  double nr= val_real();
  if (null_value)
    return 0;
  double2my_decimal(E_DEC_FATAL_ERROR, nr, decimal_value);
  return (decimal_value);
}


my_decimal *Item::val_decimal_from_int(my_decimal *decimal_value)
{
  longlong nr= val_int();
  if (null_value)
    return 0;
  int2my_decimal(E_DEC_FATAL_ERROR, nr, unsigned_flag, decimal_value);
  return decimal_value;
}


my_decimal *Item::val_decimal_from_string(my_decimal *decimal_value)
{
  String *res;
  char *end_ptr;
  if (!(res= val_str(&str_value)))
    return 0;                                   // NULL or EOM

  end_ptr= (char*) res->ptr()+ res->length();
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  if (str2my_decimal(E_DEC_FATAL_ERROR & ~E_DEC_BAD_NUM,
                     res->ptr(), res->length(), res->charset(),
                     decimal_value) & E_DEC_BAD_NUM)
  {
    push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
                        ER_TRUNCATED_WRONG_VALUE,
                        ER(ER_TRUNCATED_WRONG_VALUE), "DECIMAL",
                        str_value.c_ptr());
  }
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  return decimal_value;
}


double Item::val_real_from_decimal()
{
  /* Note that fix_fields may not be called for Item_avg_field items */
  double result;
  my_decimal value_buff, *dec_val= val_decimal(&value_buff);
  if (null_value)
    return 0.0;
  my_decimal2double(E_DEC_FATAL_ERROR, dec_val, &result);
  return result;
}


longlong Item::val_int_from_decimal()
{
  /* Note that fix_fields may not be called for Item_avg_field items */
  longlong result;
  my_decimal value, *dec_val= val_decimal(&value);
  if (null_value)
    return 0;
  my_decimal2int(E_DEC_FATAL_ERROR, dec_val, unsigned_flag, &result);
  return result;
}


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Item::Item():
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  rsize(0), name(0), orig_name(0), name_length(0), fixed(0),
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  is_autogenerated_name(TRUE),
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  collation(&my_charset_bin, DERIVATION_COERCIBLE)
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{
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  marker= 0;
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  maybe_null=null_value=with_sum_func=unsigned_flag=0;
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  decimals= 0; max_length= 0;
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  with_subselect= 0;
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  cmp_context= (Item_result)-1;
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  /* Put item in free list so that we can free all items at end */
  THD *thd= current_thd;
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  next= thd->free_list;
  thd->free_list= this;
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  /*
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    Item constructor can be called during execution other then SQL_COM
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    command => we should check thd->lex->current_select on zero (thd->lex
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    can be uninitialised)
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  */
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  if (thd->lex->current_select)
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  {
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    enum_parsing_place place= 
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      thd->lex->current_select->parsing_place;
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    if (place == SELECT_LIST ||
	place == IN_HAVING)
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      thd->lex->current_select->select_n_having_items++;
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  }
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}

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/*
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  Constructor used by Item_field, Item_*_ref & aggregate (sum) functions.
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  Used for duplicating lists in processing queries with temporary
  tables
*/
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Item::Item(THD *thd, Item *item):
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  rsize(0),
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  str_value(item->str_value),
  name(item->name),
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  orig_name(item->orig_name),
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  max_length(item->max_length),
  marker(item->marker),
  decimals(item->decimals),
  maybe_null(item->maybe_null),
  null_value(item->null_value),
  unsigned_flag(item->unsigned_flag),
  with_sum_func(item->with_sum_func),
  fixed(item->fixed),
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  collation(item->collation),
  cmp_context(item->cmp_context)
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{
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  next= thd->free_list;				// Put in free list
  thd->free_list= this;
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}

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uint Item::decimal_precision() const
{
  Item_result restype= result_type();

  if ((restype == DECIMAL_RESULT) || (restype == INT_RESULT))
    return min(my_decimal_length_to_precision(max_length, decimals, unsigned_flag),
               DECIMAL_MAX_PRECISION);
  return min(max_length, DECIMAL_MAX_PRECISION);
}


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void Item::print_item_w_name(String *str)
{
  print(str);
  if (name)
  {
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    THD *thd= current_thd;
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    str->append(STRING_WITH_LEN(" AS "));
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    append_identifier(thd, str, name, (uint) strlen(name));
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  }
}


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void Item::cleanup()
{
  DBUG_ENTER("Item::cleanup");
  fixed=0;
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  marker= 0;
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  if (orig_name)
    name= orig_name;
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  DBUG_VOID_RETURN;
}

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/*
  cleanup() item if it is 'fixed'

  SYNOPSIS
    cleanup_processor()
    arg - a dummy parameter, is not used here
*/

bool Item::cleanup_processor(byte *arg)
{
  if (fixed)
    cleanup();
  return FALSE;
}


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/*
  rename item (used for views, cleanup() return original name)

  SYNOPSIS
    Item::rename()
    new_name	new name of item;
*/

void Item::rename(char *new_name)
{
  /*
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    we can compare pointers to names here, because if name was not changed,
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    pointer will be same
  */
  if (!orig_name && new_name != name)
    orig_name= name;
  name= new_name;
}


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/*
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  Traverse item tree possibly transforming it (replacing items).
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  SYNOPSIS
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    Item::transform()
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      transformer    functor that performs transformation of a subtree
      arg            opaque argument passed to the functor

  DESCRIPTION
    This function is designed to ease transformation of Item trees.

    Re-execution note: every such transformation is registered for
    rollback by THD::change_item_tree() and is rolled back at the end
    of execution by THD::rollback_item_tree_changes().

    Therefore:

      - this function can not be used at prepared statement prepare
        (in particular, in fix_fields!), as only permanent
        transformation of Item trees are allowed at prepare.

      - the transformer function shall allocate new Items in execution
        memory root (thd->mem_root) and not anywhere else: allocated
        items will be gone in the end of execution.

    If you don't need to transform an item tree, but only traverse
    it, please use Item::walk() instead.


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  RETURN VALUE
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    Returns pointer to the new subtree root.  THD::change_item_tree()
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    should be called for it if transformation took place, i.e. if a
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    pointer to newly allocated item is returned.
*/

Item* Item::transform(Item_transformer transformer, byte *arg)
{
  DBUG_ASSERT(!current_thd->is_stmt_prepare());

  return (this->*transformer)(arg);
}


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Item_ident::Item_ident(Name_resolution_context *context_arg,
                       const char *db_name_arg,const char *table_name_arg,
		       const char *field_name_arg)
  :orig_db_name(db_name_arg), orig_table_name(table_name_arg),
   orig_field_name(field_name_arg), context(context_arg),
   db_name(db_name_arg), table_name(table_name_arg),
   field_name(field_name_arg),
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   alias_name_used(FALSE), cached_field_index(NO_CACHED_FIELD_INDEX),
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   cached_table(0), depended_from(0)
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{
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  name = (char*) field_name_arg;
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}

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/* Constructor used by Item_field & Item_*_ref (see Item comment) */
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Item_ident::Item_ident(THD *thd, Item_ident *item)
  :Item(thd, item),
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   orig_db_name(item->orig_db_name),
   orig_table_name(item->orig_table_name), 
   orig_field_name(item->orig_field_name),
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   context(item->context),
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   db_name(item->db_name),
   table_name(item->table_name),
   field_name(item->field_name),
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   alias_name_used(item->alias_name_used),
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   cached_field_index(item->cached_field_index),
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   cached_table(item->cached_table),
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   depended_from(item->depended_from)
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{}
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void Item_ident::cleanup()
{
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  DBUG_ENTER("Item_ident::cleanup");
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#ifdef CANT_BE_USED_AS_MEMORY_IS_FREED
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		       db_name ? db_name : "(null)",
                       orig_db_name ? orig_db_name : "(null)",
		       table_name ? table_name : "(null)",
                       orig_table_name ? orig_table_name : "(null)",
		       field_name ? field_name : "(null)",
                       orig_field_name ? orig_field_name : "(null)"));
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#endif
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  Item::cleanup();
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  db_name= orig_db_name; 
  table_name= orig_table_name;
  field_name= orig_field_name;
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  depended_from= 0;
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  DBUG_VOID_RETURN;
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}

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bool Item_ident::remove_dependence_processor(byte * arg)
{
  DBUG_ENTER("Item_ident::remove_dependence_processor");
  if (depended_from == (st_select_lex *) arg)
    depended_from= 0;
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  DBUG_RETURN(0);
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}


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/*
  Store the pointer to this item field into a list if not already there.

  SYNOPSIS
    Item_field::collect_item_field_processor()
    arg  pointer to a List<Item_field>

  DESCRIPTION
    The method is used by Item::walk to collect all unique Item_field objects
    from a tree of Items into a set of items represented as a list.

  IMPLEMENTATION
    Item_cond::walk() and Item_func::walk() stop the evaluation of the
    processor function for its arguments once the processor returns
    true.Therefore in order to force this method being called for all item
    arguments in a condition the method must return false.

  RETURN
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    FALSE to force the evaluation of collect_item_field_processor
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          for the subsequent items.
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*/

bool Item_field::collect_item_field_processor(byte *arg)
{
  DBUG_ENTER("Item_field::collect_item_field_processor");
  DBUG_PRINT("info", ("%s", field->field_name ? field->field_name : "noname"));
  List<Item_field> *item_list= (List<Item_field>*) arg;
  List_iterator<Item_field> item_list_it(*item_list);
  Item_field *curr_item;
  while ((curr_item= item_list_it++))
  {
    if (curr_item->eq(this, 1))
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      DBUG_RETURN(FALSE); /* Already in the set. */
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  }
  item_list->push_back(this);
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  DBUG_RETURN(FALSE);
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}


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/*
  Check if an Item_field references some field from a list of fields.

  SYNOPSIS
    Item_field::find_item_in_field_list_processor
    arg   Field being compared, arg must be of type Field

  DESCRIPTION
    Check whether the Item_field represented by 'this' references any
    of the fields in the keyparts passed via 'arg'. Used with the
    method Item::walk() to test whether any keypart in a sequence of
    keyparts is referenced in an expression.

  RETURN
    TRUE  if 'this' references the field 'arg'
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    FALSE otherwise
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*/
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bool Item_field::find_item_in_field_list_processor(byte *arg)
{
  KEY_PART_INFO *first_non_group_part= *((KEY_PART_INFO **) arg);
  KEY_PART_INFO *last_part= *(((KEY_PART_INFO **) arg) + 1);
  KEY_PART_INFO *cur_part;

  for (cur_part= first_non_group_part; cur_part != last_part; cur_part++)
  {
    if (field->eq(cur_part->field))
      return TRUE;
  }
  return FALSE;
}


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bool Item::check_cols(uint c)
{
  if (c != 1)
  {
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    my_error(ER_OPERAND_COLUMNS, MYF(0), c);
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    return 1;
  }
  return 0;
}

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void Item::set_name(const char *str, uint length, CHARSET_INFO *cs)
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{
  if (!length)
  {
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    /* Empty string, used by AS or internal function like last_insert_id() */
    name= (char*) str;
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    name_length= 0;
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    return;
  }
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  if (cs->ctype)
  {
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    uint orig_len= length;
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    /*
      This will probably need a better implementation in the future:
      a function in CHARSET_INFO structure.
    */
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    while (length && !my_isgraph(cs,*str))
    {						// Fix problem with yacc
      length--;
      str++;
    }
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    if (orig_len != length && !is_autogenerated_name)
      push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
                          ER_REMOVED_SPACES, ER(ER_REMOVED_SPACES),
                          str + length - orig_len);

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  }
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  if (!my_charset_same(cs, system_charset_info))
  {
    uint32 res_length;
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    name= sql_strmake_with_convert(str, name_length= length, cs,
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				   MAX_ALIAS_NAME, system_charset_info,
				   &res_length);
  }
  else
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    name= sql_strmake(str, (name_length= min(length,MAX_ALIAS_NAME)));
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}

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/*
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  This function is called when:
  - Comparing items in the WHERE clause (when doing where optimization)
  - When trying to find an ORDER BY/GROUP BY item in the SELECT part
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*/

bool Item::eq(const Item *item, bool binary_cmp) const
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{
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  /*
    Note, that this is never TRUE if item is a Item_param:
    for all basic constants we have special checks, and Item_param's
    type() can be only among basic constant types.
  */
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  return type() == item->type() && name && item->name &&
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    !my_strcasecmp(system_charset_info,name,item->name);
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}

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Item *Item::safe_charset_converter(CHARSET_INFO *tocs)
{
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  Item_func_conv_charset *conv= new Item_func_conv_charset(this, tocs, 1);
  return conv->safe ? conv : NULL;
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}


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/*
  Created mostly for mysql_prepare_table(). Important
  when a string ENUM/SET column is described with a numeric default value:

  CREATE TABLE t1(a SET('a') DEFAULT 1);

  We cannot use generic Item::safe_charset_converter(), because
  the latter returns a non-fixed Item, so val_str() crashes afterwards.
  Override Item_num method, to return a fixed item.
*/
Item *Item_num::safe_charset_converter(CHARSET_INFO *tocs)
{
  Item_string *conv;
  char buf[64];
  String *s, tmp(buf, sizeof(buf), &my_charset_bin);
  s= val_str(&tmp);
  if ((conv= new Item_string(s->ptr(), s->length(), s->charset())))
  {
    conv->str_value.copy();
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    conv->str_value.mark_as_const();
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  }
  return conv;
}


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Item *Item_static_float_func::safe_charset_converter(CHARSET_INFO *tocs)
{
  Item_string *conv;
  char buf[64];
  String *s, tmp(buf, sizeof(buf), &my_charset_bin);
  s= val_str(&tmp);
  if ((conv= new Item_static_string_func(func_name, s->ptr(), s->length(),
                                         s->charset())))
  {
    conv->str_value.copy();
    conv->str_value.mark_as_const();
  }
  return conv;
}


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Item *Item_string::safe_charset_converter(CHARSET_INFO *tocs)
{
  Item_string *conv;
  uint conv_errors;
  String tmp, cstr, *ostr= val_str(&tmp);
  cstr.copy(ostr->ptr(), ostr->length(), ostr->charset(), tocs, &conv_errors);
  if (conv_errors || !(conv= new Item_string(cstr.ptr(), cstr.length(),
                                             cstr.charset(),
                                             collation.derivation)))
  {
    /*
      Safe conversion is not possible (or EOM).
      We could not convert a string into the requested character set
      without data loss. The target charset does not cover all the
      characters from the string. Operation cannot be done correctly.
    */
    return NULL;
  }
  conv->str_value.copy();
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  /* Ensure that no one is going to change the result string */
  conv->str_value.mark_as_const();
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  return conv;
}


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Item *Item_param::safe_charset_converter(CHARSET_INFO *tocs)
{
  if (const_item())
  {
    uint cnv_errors;
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    String *ostr= val_str(&cnvstr);
    cnvitem->str_value.copy(ostr->ptr(), ostr->length(),
                            ostr->charset(), tocs, &cnv_errors);
    if (cnv_errors)
       return NULL;
    cnvitem->str_value.mark_as_const();
    cnvitem->max_length= cnvitem->str_value.numchars() * tocs->mbmaxlen;
    return cnvitem;
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  }
  return NULL;
}


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Item *Item_static_string_func::safe_charset_converter(CHARSET_INFO *tocs)
{
  Item_string *conv;
  uint conv_errors;
  String tmp, cstr, *ostr= val_str(&tmp);
  cstr.copy(ostr->ptr(), ostr->length(), ostr->charset(), tocs, &conv_errors);
  if (conv_errors ||
      !(conv= new Item_static_string_func(func_name,
                                          cstr.ptr(), cstr.length(),
                                          cstr.charset(),
                                          collation.derivation)))
  {
    /*
      Safe conversion is not possible (or EOM).
      We could not convert a string into the requested character set
      without data loss. The target charset does not cover all the
      characters from the string. Operation cannot be done correctly.
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    */
    return NULL;
  }
  conv->str_value.copy();
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  /* Ensure that no one is going to change the result string */
  conv->str_value.mark_as_const();
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  return conv;
}


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bool Item_string::eq(const Item *item, bool binary_cmp) const
{
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  if (type() == item->type() && item->basic_const_item())
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  {
    if (binary_cmp)
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      return !stringcmp(&str_value, &item->str_value);
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    return (collation.collation == item->collation.collation &&
	    !sortcmp(&str_value, &item->str_value, collation.collation));
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  }
  return 0;
}


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/*
  Get the value of the function as a TIME structure.
  As a extra convenience the time structure is reset on error!
 */

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bool Item::get_date(TIME *ltime,uint fuzzydate)
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{
  char buff[40];
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  String tmp(buff,sizeof(buff), &my_charset_bin),*res;
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  if (!(res=val_str(&tmp)) ||
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      str_to_datetime_with_warn(res->ptr(), res->length(),
                                ltime, fuzzydate) <= MYSQL_TIMESTAMP_ERROR)
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  {
    bzero((char*) ltime,sizeof(*ltime));
    return 1;
  }
  return 0;
}

/*
  Get time of first argument.
  As a extra convenience the time structure is reset on error!
 */

bool Item::get_time(TIME *ltime)
{
  char buff[40];
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  String tmp(buff,sizeof(buff),&my_charset_bin),*res;
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  if (!(res=val_str(&tmp)) ||
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      str_to_time_with_warn(res->ptr(), res->length(), ltime))
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  {
    bzero((char*) ltime,sizeof(*ltime));
    return 1;
  }
  return 0;
}

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CHARSET_INFO *Item::default_charset()
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{
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  return current_thd->variables.collation_connection;
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}

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int Item::save_in_field_no_warnings(Field *field, bool no_conversions)
{
  int res;
  THD *thd= field->table->in_use;
  enum_check_fields tmp= thd->count_cuted_fields;
  thd->count_cuted_fields= CHECK_FIELD_IGNORE;
  res= save_in_field(field, no_conversions);
  thd->count_cuted_fields= tmp;
  return res;
}


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/*****************************************************************************
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  Item_sp_variable methods
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*****************************************************************************/
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Item_sp_variable::Item_sp_variable(char *sp_var_name_str,
                                   uint sp_var_name_length)
  :m_thd(0)
#ifndef DBUG_OFF
   , m_sp(0)
#endif
{
  m_name.str= sp_var_name_str;
  m_name.length= sp_var_name_length;
}


bool Item_sp_variable::fix_fields(THD *thd, Item **)
{
  Item *it;

  m_thd= thd; /* NOTE: this must be set before any this_xxx() */
  it= this_item();

  DBUG_ASSERT(it->fixed);

  max_length= it->max_length;
  decimals= it->decimals;
  unsigned_flag= it->unsigned_flag;
  fixed= 1;
  collation.set(it->collation.collation, it->collation.derivation);

  return FALSE;
}


double Item_sp_variable::val_real()
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{
  DBUG_ASSERT(fixed);
  Item *it= this_item();
  double ret= it->val_real();
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  null_value= it->null_value;
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  return ret;
}


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longlong Item_sp_variable::val_int()
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{
  DBUG_ASSERT(fixed);
  Item *it= this_item();
  longlong ret= it->val_int();
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  null_value= it->null_value;
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  return ret;
}


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String *Item_sp_variable::val_str(String *sp)
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{
  DBUG_ASSERT(fixed);
  Item *it= this_item();
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  String *res= it->val_str(sp);
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  null_value= it->null_value;
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  if (!res)
    return NULL;

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  /*
    This way we mark returned value of val_str as const,
    so that various functions (e.g. CONCAT) won't try to
    modify the value of the Item. Analogous mechanism is
    implemented for Item_param.
    Without this trick Item_splocal could be changed as a
    side-effect of expression computation. Here is an example
    of what happens without it: suppose x is varchar local
    variable in a SP with initial value 'ab' Then
      select concat(x,'c');
    would change x's value to 'abc', as Item_func_concat::val_str()
    would use x's internal buffer to compute the result.
    This is intended behaviour of Item_func_concat. Comments to
    Item_param class contain some more details on the topic.
  */
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  if (res != &str_value)
    str_value.set(res->ptr(), res->length(), res->charset());
  else
    res->mark_as_const();
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  return &str_value;
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}


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my_decimal *Item_sp_variable::val_decimal(my_decimal *decimal_value)
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{
  DBUG_ASSERT(fixed);
  Item *it= this_item();
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  my_decimal *val= it->val_decimal(decimal_value);
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  null_value= it->null_value;
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  return val;
}


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bool Item_sp_variable::is_null()
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{
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  return this_item()->is_null();
}


/*****************************************************************************
  Item_splocal methods
*****************************************************************************/

Item_splocal::Item_splocal(const LEX_STRING &sp_var_name,
                           uint sp_var_idx,
                           enum_field_types sp_var_type,
                           uint pos_in_q)
  :Item_sp_variable(sp_var_name.str, sp_var_name.length),
   m_var_idx(sp_var_idx), pos_in_query(pos_in_q)
{
  maybe_null= TRUE;

  m_type= sp_map_item_type(sp_var_type);
  m_result_type= sp_map_result_type(sp_var_type);
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}


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Item *
Item_splocal::this_item()
{
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  DBUG_ASSERT(m_sp == m_thd->spcont->sp);

  return m_thd->spcont->get_item(m_var_idx);
}

const Item *
Item_splocal::this_item() const
{
  DBUG_ASSERT(m_sp == m_thd->spcont->sp);

  return m_thd->spcont->get_item(m_var_idx);
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}

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Item **
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Item_splocal::this_item_addr(THD *thd, Item **)
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{
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  DBUG_ASSERT(m_sp == thd->spcont->sp);

  return thd->spcont->get_item_addr(m_var_idx);
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}

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void Item_splocal::print(String *str)
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{
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  str->reserve(m_name.length+8);
  str->append(m_name.str, m_name.length);
  str->append('@');
  str->qs_append(m_var_idx);
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}

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bool Item_splocal::set_value(THD *thd, sp_rcontext *ctx, Item **it)
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{
  return ctx->set_variable(thd, get_var_idx(), it);
}


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/*****************************************************************************
  Item_case_expr methods
*****************************************************************************/

Item_case_expr::Item_case_expr(int case_expr_id)
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  :Item_sp_variable((char *) STRING_WITH_LEN("case_expr")),
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   m_case_expr_id(case_expr_id)
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{
}


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Item *
Item_case_expr::this_item()
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{
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  DBUG_ASSERT(m_sp == m_thd->spcont->sp);

  return m_thd->spcont->get_case_expr(m_case_expr_id);
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}


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const Item *
Item_case_expr::this_item() const
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{
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  DBUG_ASSERT(m_sp == m_thd->spcont->sp);

  return m_thd->spcont->get_case_expr(m_case_expr_id);
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}


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Item **
Item_case_expr::this_item_addr(THD *thd, Item **)
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{
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  DBUG_ASSERT(m_sp == thd->spcont->sp);

  return thd->spcont->get_case_expr_addr(m_case_expr_id);
}


void Item_case_expr::print(String *str)
{
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  VOID(str->append(STRING_WITH_LEN("case_expr@")));
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  str->qs_append(m_case_expr_id);
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}


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/*****************************************************************************
  Item_name_const methods
*****************************************************************************/
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double Item_name_const::val_real()
{
  DBUG_ASSERT(fixed);
  double ret= value_item->val_real();
  null_value= value_item->null_value;
  return ret;
}


longlong Item_name_const::val_int()
{
  DBUG_ASSERT(fixed);
  longlong ret= value_item->val_int();
  null_value= value_item->null_value;
  return ret;
}


String *Item_name_const::val_str(String *sp)
{
  DBUG_ASSERT(fixed);
  String *ret= value_item->val_str(sp);
  null_value= value_item->null_value;
  return ret;
}


my_decimal *Item_name_const::val_decimal(my_decimal *decimal_value)
{
  DBUG_ASSERT(fixed);
  my_decimal *val= value_item->val_decimal(decimal_value);
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  null_value= value_item->null_value;
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  return val;
}


bool Item_name_const::is_null()
{
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  return value_item->is_null();
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}

Item::Type Item_name_const::type() const
{
  return value_item->type();
}


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bool Item_name_const::fix_fields(THD *thd, Item **ref)
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{
  char buf[128];
  String *item_name;
  String s(buf, sizeof(buf), &my_charset_bin);
  s.length(0);

  if (value_item->fix_fields(thd, &value_item) ||
      name_item->fix_fields(thd, &name_item))
    return TRUE;
  if (!(value_item->const_item() && name_item->const_item()))
    return TRUE;

  if (!(item_name= name_item->val_str(&s)))
    return TRUE; /* Can't have a NULL name */

  set_name(item_name->ptr(), (uint) item_name->length(), system_charset_info);
  max_length= value_item->max_length;
  decimals= value_item->decimals;
  fixed= 1;
  return FALSE;
}


void Item_name_const::print(String *str)
{
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  str->append(STRING_WITH_LEN("NAME_CONST("));
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  name_item->print(str);
  str->append(',');
  value_item->print(str);
  str->append(')');
}

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/*
  Move SUM items out from item tree and replace with reference

  SYNOPSIS
    split_sum_func2()
    thd			Thread handler
    ref_pointer_array	Pointer to array of reference fields
    fields		All fields in select
    ref			Pointer to item
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    skip_registered     <=> function be must skipped for registered SUM items
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  NOTES
   This is from split_sum_func2() for items that should be split

   All found SUM items are added FIRST in the fields list and
   we replace the item with a reference.

   thd->fatal_error() may be called if we are out of memory
*/


void Item::split_sum_func2(THD *thd, Item **ref_pointer_array,
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                           List<Item> &fields, Item **ref, 
                           bool skip_registered)
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{
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  /* An item of type Item_sum  is registered <=> ref_by != 0 */ 
  if (type() == SUM_FUNC_ITEM && skip_registered && 
      ((Item_sum *) this)->ref_by)
    return;                                                 
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  if (type() != SUM_FUNC_ITEM && with_sum_func)
  {
    /* Will split complicated items and ignore simple ones */
    split_sum_func(thd, ref_pointer_array, fields);
  }
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  else if ((type() == SUM_FUNC_ITEM || (used_tables() & ~PARAM_TABLE_BIT)) &&
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           type() != SUBSELECT_ITEM &&
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           (type() != REF_ITEM ||
           ((Item_ref*)this)->ref_type() == Item_ref::VIEW_REF))
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  {
    /*
      Replace item with a reference so that we can easily calculate
      it (in case of sum functions) or copy it (in case of fields)

      The test above is to ensure we don't do a reference for things
      that are constants (PARAM_TABLE_BIT is in effect a constant)
      or already referenced (for example an item in HAVING)
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      Exception is Item_direct_view_ref which we need to convert to
      Item_ref to allow fields from view being stored in tmp table.
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    */
    uint el= fields.elements;
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    Item *new_item, *real_itm= real_item();
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    ref_pointer_array[el]= real_itm;
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    if (!(new_item= new Item_ref(&thd->lex->current_select->context,
                                 ref_pointer_array + el, 0, name)))
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      return;                                   // fatal_error is set
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    fields.push_front(real_itm);
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    thd->change_item_tree(ref, new_item);
  }
}


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/*
   Aggregate two collations together taking
   into account their coercibility (aka derivation):

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   0 == DERIVATION_EXPLICIT  - an explicitly written COLLATE clause
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   1 == DERIVATION_NONE      - a mix of two different collations
   2 == DERIVATION_IMPLICIT  - a column
   3 == DERIVATION_COERCIBLE - a string constant

   The most important rules are:

   1. If collations are the same:
      chose this collation, and the strongest derivation.

   2. If collations are different:
     - Character sets may differ, but only if conversion without
       data loss is possible. The caller provides flags whether
       character set conversion attempts should be done. If no
       flags are substituted, then the character sets must be the same.
       Currently processed flags are:
         MY_COLL_ALLOW_SUPERSET_CONV  - allow conversion to a superset
         MY_COLL_ALLOW_COERCIBLE_CONV - allow conversion of a coercible value
     - two EXPLICIT collations produce an error, e.g. this is wrong:
       CONCAT(expr1 collate latin1_swedish_ci, expr2 collate latin1_german_ci)
     - the side with smaller derivation value wins,
       i.e. a column is stronger than a string constant,
       an explicit COLLATE clause is stronger than a column.
     - if derivations are the same, we have DERIVATION_NONE,
       we'll wait for an explicit COLLATE clause which possibly can
       come from another argument later: for example, this is valid,
       but we don't know yet when collecting the first two arguments:
         CONCAT(latin1_swedish_ci_column,
                latin1_german1_ci_column,
                expr COLLATE latin1_german2_ci)
*/
bool DTCollation::aggregate(DTCollation &dt, uint flags)
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{
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  if (!my_charset_same(collation, dt.collation))
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  {
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    /* 
       We do allow to use binary strings (like BLOBS)
       together with character strings.
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       Binaries have more precedence than a character
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       string of the same derivation.
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    */
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    if (collation == &my_charset_bin)
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    {
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      if (derivation <= dt.derivation)
	; // Do nothing
      else
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      {
	set(dt); 
      }
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    }
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    else if (dt.collation == &my_charset_bin)
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    {
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      if (dt.derivation <= derivation)
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      {
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        set(dt);
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      }
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      else
       ; // Do nothing
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    }
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    else if ((flags & MY_COLL_ALLOW_SUPERSET_CONV) &&
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             collation->state & MY_CS_UNICODE &&
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             (derivation < dt.derivation ||
             (derivation == dt.derivation &&
             !(dt.collation->state & MY_CS_UNICODE))))
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    {
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      // Do nothing
    }
    else if ((flags & MY_COLL_ALLOW_SUPERSET_CONV) &&
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             dt.collation->state & MY_CS_UNICODE &&
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             (dt.derivation < derivation ||
              (dt.derivation == derivation &&
             !(collation->state & MY_CS_UNICODE))))
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    {
      set(dt);
    }
    else if ((flags & MY_COLL_ALLOW_COERCIBLE_CONV) &&
             derivation < dt.derivation &&
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             dt.derivation >= DERIVATION_SYSCONST)
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    {
      // Do nothing;
    }
    else if ((flags & MY_COLL_ALLOW_COERCIBLE_CONV) &&
             dt.derivation < derivation &&
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             derivation >= DERIVATION_SYSCONST)
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    {
      set(dt);
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    }
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    else
    {
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      // Cannot apply conversion
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      set(0, DERIVATION_NONE);
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      return 1;
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    }
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  }
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  else if (derivation < dt.derivation)
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  {
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    // Do nothing
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  }
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  else if (dt.derivation < derivation)
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  {
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    set(dt);
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  }
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  else
  { 
    if (collation == dt.collation)
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    {
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      // Do nothing
    }
    else 
    {
      if (derivation == DERIVATION_EXPLICIT)
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      {
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	set(0, DERIVATION_NONE);
	return 1;
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      }
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      if (collation->state & MY_CS_BINSORT)
        return 0;
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      if (dt.collation->state & MY_CS_BINSORT)
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      {
        set(dt);
        return 0;
      }
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      CHARSET_INFO *bin= get_charset_by_csname(collation->csname, 
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                                               MY_CS_BINSORT,MYF(0));
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      set(bin, DERIVATION_NONE);
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    }
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  }
  return 0;
}

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/******************************/
static
void my_coll_agg_error(DTCollation &c1, DTCollation &c2, const char *fname)
{
  my_error(ER_CANT_AGGREGATE_2COLLATIONS,MYF(0),
           c1.collation->name,c1.derivation_name(),
           c2.collation->name,c2.derivation_name(),
           fname);
}


static
void my_coll_agg_error(DTCollation &c1, DTCollation &c2, DTCollation &c3,
                       const char *fname)
{
  my_error(ER_CANT_AGGREGATE_3COLLATIONS,MYF(0),
  	   c1.collation->name,c1.derivation_name(),
	   c2.collation->name,c2.derivation_name(),
	   c3.collation->name,c3.derivation_name(),
	   fname);
}


static
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void my_coll_agg_error(Item** args, uint count, const char *fname,
                       int item_sep)
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{
  if (count == 2)
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    my_coll_agg_error(args[0]->collation, args[item_sep]->collation, fname);
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  else if (count == 3)
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    my_coll_agg_error(args[0]->collation, args[item_sep]->collation,
                      args[2*item_sep]->collation, fname);
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  else
    my_error(ER_CANT_AGGREGATE_NCOLLATIONS,MYF(0),fname);
}


bool agg_item_collations(DTCollation &c, const char *fname,
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                         Item **av, uint count, uint flags, int item_sep)
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{
  uint i;
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  Item **arg;
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  c.set(av[0]->collation);
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  for (i= 1, arg= &av[item_sep]; i < count; i++, arg++)
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  {
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    if (c.aggregate((*arg)->collation, flags))
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    {
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      my_coll_agg_error(av, count, fname, item_sep);
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      return TRUE;
    }
  }
  if ((flags & MY_COLL_DISALLOW_NONE) &&
      c.derivation == DERIVATION_NONE)
  {
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    my_coll_agg_error(av, count, fname, item_sep);
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    return TRUE;
  }
  return FALSE;
}


bool agg_item_collations_for_comparison(DTCollation &c, const char *fname,
                                        Item **av, uint count, uint flags)
{
  return (agg_item_collations(c, fname, av, count,
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                              flags | MY_COLL_DISALLOW_NONE, 1));
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}


/* 
  Collect arguments' character sets together.
  We allow to apply automatic character set conversion in some cases.
  The conditions when conversion is possible are:
  - arguments A and B have different charsets
  - A wins according to coercibility rules
    (i.e. a column is stronger than a string constant,
     an explicit COLLATE clause is stronger than a column)
  - character set of A is either superset for character set of B,
    or B is a string constant which can be converted into the
    character set of A without data loss.
    
  If all of the above is true, then it's possible to convert
  B into the character set of A, and then compare according
  to the collation of A.
  
  For functions with more than two arguments:

    collect(A,B,C) ::= collect(collect(A,B),C)
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  Since this function calls THD::change_item_tree() on the passed Item **
  pointers, it is necessary to pass the original Item **'s, not copies.
  Otherwise their values will not be properly restored (see BUG#20769).
  If the items are not consecutive (eg. args[2] and args[5]), use the
  item_sep argument, ie.

    agg_item_charsets(coll, fname, &args[2], 2, flags, 3)

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*/

bool agg_item_charsets(DTCollation &coll, const char *fname,
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                       Item **args, uint nargs, uint flags, int item_sep)
1447
{
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  Item **arg, *safe_args[2];
  if (agg_item_collations(coll, fname, args, nargs, flags, item_sep))
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    return TRUE;

  /*
    For better error reporting: save the first and the second argument.
    We need this only if the the number of args is 3 or 2:
    - for a longer argument list, "Illegal mix of collations"
      doesn't display each argument's characteristics.
    - if nargs is 1, then this error cannot happen.
  */
  if (nargs >=2 && nargs <= 3)
  {
    safe_args[0]= args[0];
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    safe_args[1]= args[item_sep];
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  }

  THD *thd= current_thd;
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  Query_arena *arena, backup;
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  bool res= FALSE;
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  uint i;
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  /*
    In case we're in statement prepare, create conversion item
    in its memory: it will be reused on each execute.
  */
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  arena= thd->is_stmt_prepare() ? thd->activate_stmt_arena_if_needed(&backup)
                                : NULL;
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  for (i= 0, arg= args; i < nargs; i++, arg+= item_sep)
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  {
    Item* conv;
    uint32 dummy_offset;
    if (!String::needs_conversion(0, coll.collation,
                                  (*arg)->collation.collation,
                                  &dummy_offset))
      continue;

    if (!(conv= (*arg)->safe_charset_converter(coll.collation)))
    {
      if (nargs >=2 && nargs <= 3)
      {
        /* restore the original arguments for better error message */
        args[0]= safe_args[0];
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        args[item_sep]= safe_args[1];
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      }
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      my_coll_agg_error(args, nargs, fname, item_sep);
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      res= TRUE;
      break; // we cannot return here, we need to restore "arena".
    }
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    if ((*arg)->type() == Item::FIELD_ITEM)
      ((Item_field *)(*arg))->no_const_subst= 1;
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    /*
      If in statement prepare, then we create a converter for two
      constant items, do it once and then reuse it.
      If we're in execution of a prepared statement, arena is NULL,
      and the conv was created in runtime memory. This can be
      the case only if the argument is a parameter marker ('?'),
      because for all true constants the charset converter has already
      been created in prepare. In this case register the change for
      rollback.
    */
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    if (arena)
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      *arg= conv;
    else
      thd->change_item_tree(arg, conv);
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    /*
      We do not check conv->fixed, because Item_func_conv_charset which can
      be return by safe_charset_converter can't be fixed at creation
    */
    conv->fix_fields(thd, arg);
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  }
  if (arena)
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    thd->restore_active_arena(arena, &backup);
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  return res;
}


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void Item_ident_for_show::make_field(Send_field *tmp_field)
{
  tmp_field->table_name= tmp_field->org_table_name= table_name;
  tmp_field->db_name= db_name;
  tmp_field->col_name= tmp_field->org_col_name= field->field_name;
  tmp_field->charsetnr= field->charset()->number;
  tmp_field->length=field->field_length;
  tmp_field->type=field->type();
  tmp_field->flags= field->table->maybe_null ? 
    (field->flags & ~NOT_NULL_FLAG) : field->flags;
  tmp_field->decimals= 0;
}
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/**********************************************/

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Item_field::Item_field(Field *f)
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  :Item_ident(0, NullS, *f->table_name, f->field_name),
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  item_equal(0), no_const_subst(0),
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   have_privileges(0), any_privileges(0)
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{
  set_field(f);
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  /*
    field_name and talbe_name should not point to garbage
    if this item is to be reused
  */
  orig_table_name= orig_field_name= "";
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}

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Item_field::Item_field(THD *thd, Name_resolution_context *context_arg,
                       Field *f)
  :Item_ident(context_arg, f->table->s->db, *f->table_name, f->field_name),
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   item_equal(0), no_const_subst(0),
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   have_privileges(0), any_privileges(0)
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{
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  /*
    We always need to provide Item_field with a fully qualified field
    name to avoid ambiguity when executing prepared statements like
    SELECT * from d1.t1, d2.t1; (assuming d1.t1 and d2.t1 have columns
    with same names).
    This is because prepared statements never deal with wildcards in
    select list ('*') and always fix fields using fully specified path
    (i.e. db.table.column).
    No check for OOM: if db_name is NULL, we'll just get
    "Field not found" error.
    We need to copy db_name, table_name and field_name because they must
    be allocated in the statement memory, not in table memory (the table
    structure can go away and pop up again between subsequent executions
    of a prepared statement).
  */
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  if (thd->stmt_arena->is_stmt_prepare_or_first_sp_execute())
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  {
    if (db_name)
      orig_db_name= thd->strdup(db_name);
    orig_table_name= thd->strdup(table_name);
    orig_field_name= thd->strdup(field_name);
    /*
      We don't restore 'name' in cleanup because it's not changed
      during execution. Still we need it to point to persistent
      memory if this item is to be reused.
    */
    name= (char*) orig_field_name;
  }
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  set_field(f);
}

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Item_field::Item_field(Name_resolution_context *context_arg,
                       const char *db_arg,const char *table_name_arg,
                       const char *field_name_arg)
  :Item_ident(context_arg, db_arg,table_name_arg,field_name_arg),
   field(0), result_field(0), item_equal(0), no_const_subst(0),
   have_privileges(0), any_privileges(0)
{
  collation.set(DERIVATION_IMPLICIT);
}

1601
// Constructor need to process subselect with temporary tables (see Item)
1602
Item_field::Item_field(THD *thd, Item_field *item)
1603
  :Item_ident(thd, item),
1604
   field(item->field),
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   result_field(item->result_field),
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   item_equal(item->item_equal),
   no_const_subst(item->no_const_subst),
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   have_privileges(item->have_privileges),
   any_privileges(item->any_privileges)
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{
  collation.set(DERIVATION_IMPLICIT);
}
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void Item_field::set_field(Field *field_par)
{
  field=result_field=field_par;			// for easy coding with fields
  maybe_null=field->maybe_null();
  decimals= field->decimals();
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  max_length= field_par->max_length();
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  table_name= *field_par->table_name;
  field_name= field_par->field_name;
  db_name= field_par->table->s->db;
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  alias_name_used= field_par->table->alias_name_used;
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  unsigned_flag=test(field_par->flags & UNSIGNED_FLAG);
1625
  collation.set(field_par->charset(), DERIVATION_IMPLICIT);
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  fixed= 1;
}


/*
  Reset this item to point to a field from the new temporary table.
  This is used when we create a new temporary table for each execution
  of prepared statement.
*/

void Item_field::reset_field(Field *f)
{
  set_field(f);
  /* 'name' is pointing at field->field_name of old field */
  name= (char*) f->field_name;
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}

const char *Item_ident::full_name() const
{
  char *tmp;
1646
  if (!table_name || !field_name)
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    return field_name ? field_name : name ? name : "tmp_field";
1648
  if (db_name && db_name[0])
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  {
1650 1651
    tmp=(char*) sql_alloc((uint) strlen(db_name)+(uint) strlen(table_name)+
			  (uint) strlen(field_name)+3);
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    strxmov(tmp,db_name,".",table_name,".",field_name,NullS);
  }
  else
  {
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    if (table_name[0])
    {
      tmp= (char*) sql_alloc((uint) strlen(table_name) +
			     (uint) strlen(field_name) + 2);
      strxmov(tmp, table_name, ".", field_name, NullS);
    }
    else
      tmp= (char*) field_name;
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  }
  return tmp;
}

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void Item_ident::print(String *str)
{
1670
  THD *thd= current_thd;
1671 1672
  char d_name_buff[MAX_ALIAS_NAME], t_name_buff[MAX_ALIAS_NAME];
  const char *d_name= db_name, *t_name= table_name;
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  if (lower_case_table_names== 1 ||
      (lower_case_table_names == 2 && !alias_name_used))
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  {
    if (table_name && table_name[0])
    {
      strmov(t_name_buff, table_name);
      my_casedn_str(files_charset_info, t_name_buff);
      t_name= t_name_buff;
    }
    if (db_name && db_name[0])
    {
      strmov(d_name_buff, db_name);
      my_casedn_str(files_charset_info, d_name_buff);
      d_name= d_name_buff;
    }
  }

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  if (!table_name || !field_name)
  {
1692
    const char *nm= field_name ? field_name : name ? name : "tmp_field";
1693
    append_identifier(thd, str, nm, (uint) strlen(nm));
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    return;
  }
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  if (db_name && db_name[0] && !alias_name_used)
1697
  {
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    if (!(cached_table && cached_table->belong_to_view &&
          cached_table->belong_to_view->compact_view_format))
    {
1701
      append_identifier(thd, str, d_name, (uint)strlen(d_name));
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      str->append('.');
    }
1704
    append_identifier(thd, str, t_name, (uint)strlen(t_name));
1705
    str->append('.');
1706
    append_identifier(thd, str, field_name, (uint)strlen(field_name));
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  }
  else
  {
    if (table_name[0])
    {
1712
      append_identifier(thd, str, t_name, (uint) strlen(t_name));
1713
      str->append('.');
1714
      append_identifier(thd, str, field_name, (uint) strlen(field_name));
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    }
    else
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      append_identifier(thd, str, field_name, (uint) strlen(field_name));
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  }
}

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/* ARGSUSED */
String *Item_field::val_str(String *str)
{
1724
  DBUG_ASSERT(fixed == 1);
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  if ((null_value=field->is_null()))
    return 0;
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  str->set_charset(str_value.charset());
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  return field->val_str(str,&str_value);
}

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1732
double Item_field::val_real()
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{
1734
  DBUG_ASSERT(fixed == 1);
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  if ((null_value=field->is_null()))
    return 0.0;
  return field->val_real();
}

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longlong Item_field::val_int()
{
1743
  DBUG_ASSERT(fixed == 1);
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  if ((null_value=field->is_null()))
    return 0;
  return field->val_int();
}


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my_decimal *Item_field::val_decimal(my_decimal *decimal_value)
{
  if ((null_value= field->is_null()))
    return 0;
  return field->val_decimal(decimal_value);
}


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String *Item_field::str_result(String *str)
{
  if ((null_value=result_field->is_null()))
    return 0;
1762
  str->set_charset(str_value.charset());
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  return result_field->val_str(str,&str_value);
}

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bool Item_field::get_date(TIME *ltime,uint fuzzydate)
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{
  if ((null_value=field->is_null()) || field->get_date(ltime,fuzzydate))
  {
    bzero((char*) ltime,sizeof(*ltime));
    return 1;
  }
  return 0;
}

1776
bool Item_field::get_date_result(TIME *ltime,uint fuzzydate)
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{
  if ((null_value=result_field->is_null()) ||
      result_field->get_date(ltime,fuzzydate))
  {
    bzero((char*) ltime,sizeof(*ltime));
    return 1;
  }
  return 0;
}

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bool Item_field::get_time(TIME *ltime)
{
  if ((null_value=field->is_null()) || field->get_time(ltime))
  {
    bzero((char*) ltime,sizeof(*ltime));
    return 1;
  }
  return 0;
}

double Item_field::val_result()
{
  if ((null_value=result_field->is_null()))
    return 0.0;
  return result_field->val_real();
}

longlong Item_field::val_int_result()
{
  if ((null_value=result_field->is_null()))
    return 0;
  return result_field->val_int();
}

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my_decimal *Item_field::val_decimal_result(my_decimal *decimal_value)
{
  if ((null_value= result_field->is_null()))
    return 0;
  return result_field->val_decimal(decimal_value);
}


bool Item_field::val_bool_result()
{
  if ((null_value= result_field->is_null()))
    return FALSE;
1824
  switch (result_field->result_type()) {
1825
  case INT_RESULT:
1826
    return result_field->val_int() != 0;
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  case DECIMAL_RESULT:
  {
    my_decimal decimal_value;
    my_decimal *val= result_field->val_decimal(&decimal_value);
    if (val)
      return !my_decimal_is_zero(val);
    return 0;
  }
  case REAL_RESULT:
  case STRING_RESULT:
    return result_field->val_real() != 0.0;
  case ROW_RESULT:
  default:
    DBUG_ASSERT(0);
1841
    return 0;                                   // Shut up compiler
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  }
}


1846
bool Item_field::eq(const Item *item, bool binary_cmp) const
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{
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  if (item->type() != FIELD_ITEM)
    return 0;
  
  Item_field *item_field= (Item_field*) item;
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  if (item_field->field && field)
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    return item_field->field == field;
  /*
    We may come here when we are trying to find a function in a GROUP BY
    clause from the select list.
    In this case the '100 % correct' way to do this would be to first
    run fix_fields() on the GROUP BY item and then retry this function, but
    I think it's better to relax the checking a bit as we will in
    most cases do the correct thing by just checking the field name.
    (In cases where we would choose wrong we would have to generate a
    ER_NON_UNIQ_ERROR).
  */
  return (!my_strcasecmp(system_charset_info, item_field->name,
			 field_name) &&
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	  (!item_field->table_name || !table_name ||
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	   (!my_strcasecmp(table_alias_charset, item_field->table_name,
			   table_name) &&
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	    (!item_field->db_name || !db_name ||
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	     (item_field->db_name && !strcmp(item_field->db_name,
					     db_name))))));
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}

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table_map Item_field::used_tables() const
{
  if (field->table->const_table)
    return 0;					// const item
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  return (depended_from ? OUTER_REF_TABLE_BIT : field->table->map);
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}

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Item *Item_field::get_tmp_table_item(THD *thd)
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{
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  Item_field *new_item= new Item_field(thd, this);
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  if (new_item)
    new_item->field= new_item->result_field;
  return new_item;
}
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/*
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  Create an item from a string we KNOW points to a valid longlong
  end \0 terminated number string.
  This is always 'signed'. Unsigned values are created with Item_uint()
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*/

Item_int::Item_int(const char *str_arg, uint length)
{
  char *end_ptr= (char*) str_arg + length;
  int error;
  value= my_strtoll10(str_arg, &end_ptr, &error);
  max_length= (uint) (end_ptr - str_arg);
  name= (char*) str_arg;
  fixed= 1;
}


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my_decimal *Item_int::val_decimal(my_decimal *decimal_value)
{
  int2my_decimal(E_DEC_FATAL_ERROR, value, unsigned_flag, decimal_value);
  return decimal_value;
}

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String *Item_int::val_str(String *str)
{
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  // following assert is redundant, because fixed=1 assigned in constructor
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  DBUG_ASSERT(fixed == 1);
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  str->set(value, &my_charset_bin);
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  return str;
}

void Item_int::print(String *str)
{
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  // my_charset_bin is good enough for numbers
  str_value.set(value, &my_charset_bin);
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  str->append(str_value);
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}

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Item_uint::Item_uint(const char *str_arg, uint length):
  Item_int(str_arg, length)
{
  unsigned_flag= 1;
}


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Item_uint::Item_uint(const char *str_arg, longlong i, uint length):
  Item_int(str_arg, i, length)
{
  unsigned_flag= 1;
}


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String *Item_uint::val_str(String *str)
{
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  // following assert is redundant, because fixed=1 assigned in constructor
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  DBUG_ASSERT(fixed == 1);
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  str->set((ulonglong) value, &my_charset_bin);
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  return str;
}

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void Item_uint::print(String *str)
{
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  // latin1 is good enough for numbers
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  str_value.set((ulonglong) value, default_charset());
  str->append(str_value);
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}

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Item_decimal::Item_decimal(const char *str_arg, uint length,
                           CHARSET_INFO *charset)
{
  str2my_decimal(E_DEC_FATAL_ERROR, str_arg, length, charset, &decimal_value);
  name= (char*) str_arg;
  decimals= (uint8) decimal_value.frac;
  fixed= 1;
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  max_length= my_decimal_precision_to_length(decimal_value.intg + decimals,
                                             decimals, unsigned_flag);
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}

Item_decimal::Item_decimal(longlong val, bool unsig)
{
  int2my_decimal(E_DEC_FATAL_ERROR, val, unsig, &decimal_value);
  decimals= (uint8) decimal_value.frac;
  fixed= 1;
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  max_length= my_decimal_precision_to_length(decimal_value.intg + decimals,
                                             decimals, unsigned_flag);
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}


Item_decimal::Item_decimal(double val, int precision, int scale)
{
  double2my_decimal(E_DEC_FATAL_ERROR, val, &decimal_value);
  decimals= (uint8) decimal_value.frac;
  fixed= 1;
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  max_length= my_decimal_precision_to_length(decimal_value.intg + decimals,
                                             decimals, unsigned_flag);
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}


Item_decimal::Item_decimal(const char *str, const my_decimal *val_arg,
                           uint decimal_par, uint length)
{
  my_decimal2decimal(val_arg, &decimal_value);
  name= (char*) str;
  decimals= (uint8) decimal_par;
  max_length= length;
  fixed= 1;
}


Item_decimal::Item_decimal(my_decimal *value_par)
{
  my_decimal2decimal(value_par, &decimal_value);
  decimals= (uint8) decimal_value.frac;
  fixed= 1;
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  max_length= my_decimal_precision_to_length(decimal_value.intg + decimals,
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                                             decimals, unsigned_flag);
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}


Item_decimal::Item_decimal(const char *bin, int precision, int scale)
{
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  binary2my_decimal(E_DEC_FATAL_ERROR, bin,
                    &decimal_value, precision, scale);
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  decimals= (uint8) decimal_value.frac;
  fixed= 1;
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  max_length= my_decimal_precision_to_length(precision, decimals,
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                                             unsigned_flag);
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}


longlong Item_decimal::val_int()
{
  longlong result;
  my_decimal2int(E_DEC_FATAL_ERROR, &decimal_value, unsigned_flag, &result);
  return result;
}

double Item_decimal::val_real()
{
  double result;
  my_decimal2double(E_DEC_FATAL_ERROR, &decimal_value, &result);
  return result;
}

String *Item_decimal::val_str(String *result)
{
  result->set_charset(&my_charset_bin);
  my_decimal2string(E_DEC_FATAL_ERROR, &decimal_value, 0, 0, 0, result);
  return result;
}

void Item_decimal::print(String *str)
{
  my_decimal2string(E_DEC_FATAL_ERROR, &decimal_value, 0, 0, 0, &str_value);
  str->append(str_value);
}


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bool Item_decimal::eq(const Item *item, bool binary_cmp) const
{
  if (type() == item->type() && item->basic_const_item())
  {
    /*
      We need to cast off const to call val_decimal(). This should
      be OK for a basic constant. Additionally, we can pass 0 as
      a true decimal constant will return its internal decimal
      storage and ignore the argument.
    */
    Item *arg= (Item*) item;
    my_decimal *value= arg->val_decimal(0);
    return !my_decimal_cmp(&decimal_value, value);
  }
  return 0;
}


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void Item_decimal::set_decimal_value(my_decimal *value_par)
{
  my_decimal2decimal(value_par, &decimal_value);
  decimals= (uint8) decimal_value.frac;
  unsigned_flag= !decimal_value.sign();
  max_length= my_decimal_precision_to_length(decimal_value.intg + decimals,
                                             decimals, unsigned_flag);
}


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String *Item_float::val_str(String *str)
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{
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  // following assert is redundant, because fixed=1 assigned in constructor
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  DBUG_ASSERT(fixed == 1);
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  str->set(value,decimals,&my_charset_bin);
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  return str;
}

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my_decimal *Item_float::val_decimal(my_decimal *decimal_value)
{
  // following assert is redundant, because fixed=1 assigned in constructor
  DBUG_ASSERT(fixed == 1);
  double2my_decimal(E_DEC_FATAL_ERROR, value, decimal_value);
  return (decimal_value);
}


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void Item_string::print(String *str)
{
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  str->append('_');
  str->append(collation.collation->csname);
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  str->append('\'');
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  str_value.print(str);
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  str->append('\'');
}

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inline bool check_if_only_end_space(CHARSET_INFO *cs, char *str, char *end)
{
  return str+ cs->cset->scan(cs, str, end, MY_SEQ_SPACES) == end;
}


double Item_string::val_real()
{
  DBUG_ASSERT(fixed == 1);
  int error;
  char *end, *org_end;
  double tmp;
  CHARSET_INFO *cs= str_value.charset();

  org_end= (char*) str_value.ptr() + str_value.length();
  tmp= my_strntod(cs, (char*) str_value.ptr(), str_value.length(), &end,
                  &error);
  if (error || (end != org_end && !check_if_only_end_space(cs, end, org_end)))
  {
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    /*
      We can use str_value.ptr() here as Item_string is gurantee to put an
      end \0 here.
    */
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    push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
                        ER_TRUNCATED_WRONG_VALUE,
                        ER(ER_TRUNCATED_WRONG_VALUE), "DOUBLE",
                        str_value.ptr());
  }
  return tmp;
}


longlong Item_string::val_int()
{
  DBUG_ASSERT(fixed == 1);
  int err;
  longlong tmp;
  char *end= (char*) str_value.ptr()+ str_value.length();
  char *org_end= end;
  CHARSET_INFO *cs= str_value.charset();

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  tmp= (*(cs->cset->strtoll10))(cs, str_value.ptr(), &end, &err);
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  /*
    TODO: Give error if we wanted a signed integer and we got an unsigned
    one
  */
  if (err > 0 ||
      (end != org_end && !check_if_only_end_space(cs, end, org_end)))
  {
    push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
                        ER_TRUNCATED_WRONG_VALUE,
                        ER(ER_TRUNCATED_WRONG_VALUE), "INTEGER",
                        str_value.ptr());
  }
  return tmp;
}


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my_decimal *Item_string::val_decimal(my_decimal *decimal_value)
{
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  return val_decimal_from_string(decimal_value);
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}


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bool Item_null::eq(const Item *item, bool binary_cmp) const
{ return item->type() == type(); }
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double Item_null::val_real()
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{
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  // following assert is redundant, because fixed=1 assigned in constructor
  DBUG_ASSERT(fixed == 1);
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  null_value=1;
  return 0.0;
}
longlong Item_null::val_int()
{
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  // following assert is redundant, because fixed=1 assigned in constructor
  DBUG_ASSERT(fixed == 1);
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  null_value=1;
  return 0;
}
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/* ARGSUSED */
String *Item_null::val_str(String *str)
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{
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  // following assert is redundant, because fixed=1 assigned in constructor
  DBUG_ASSERT(fixed == 1);
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  null_value=1;
  return 0;
}
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my_decimal *Item_null::val_decimal(my_decimal *decimal_value)
{
  return 0;
}

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Item *Item_null::safe_charset_converter(CHARSET_INFO *tocs)
{
  collation.set(tocs);
  return this;
}

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/*********************** Item_param related ******************************/

/* 
  Default function of Item_param::set_param_func, so in case
  of malformed packet the server won't SIGSEGV
*/

static void
default_set_param_func(Item_param *param,
                       uchar **pos __attribute__((unused)),
                       ulong len __attribute__((unused)))
{
  param->set_null();
}

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Item_param::Item_param(unsigned pos_in_query_arg) :
  state(NO_VALUE),
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  item_result_type(STRING_RESULT),
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  /* Don't pretend to be a literal unless value for this item is set. */
  item_type(PARAM_ITEM),
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  param_type(MYSQL_TYPE_VARCHAR),
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  pos_in_query(pos_in_query_arg),
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  set_param_func(default_set_param_func)
{
  name= (char*) "?";
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  /* 
    Since we can't say whenever this item can be NULL or cannot be NULL
    before mysql_stmt_execute(), so we assuming that it can be NULL until
    value is set.
  */
  maybe_null= 1;
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  cnvitem= new Item_string("", 0, &my_charset_bin, DERIVATION_COERCIBLE);
  cnvstr.set(cnvbuf, sizeof(cnvbuf), &my_charset_bin);
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}
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void Item_param::set_null()
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{
  DBUG_ENTER("Item_param::set_null");
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  /* These are cleared after each execution by reset() method */
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  null_value= 1;
  /* 
    Because of NULL and string values we need to set max_length for each new
    placeholder value: user can submit NULL for any placeholder type, and 
    string length can be different in each execution.
  */
  max_length= 0;
  decimals= 0;
  state= NULL_VALUE;
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  item_type= Item::NULL_ITEM;
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  DBUG_VOID_RETURN;
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}

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void Item_param::set_int(longlong i, uint32 max_length_arg)
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{
  DBUG_ENTER("Item_param::set_int");
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  value.integer= (longlong) i;
  state= INT_VALUE;
  max_length= max_length_arg;
  decimals= 0;
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  maybe_null= 0;
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  DBUG_VOID_RETURN;
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}

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void Item_param::set_double(double d)
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{
  DBUG_ENTER("Item_param::set_double");
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  value.real= d;
  state= REAL_VALUE;
  max_length= DBL_DIG + 8;
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  decimals= NOT_FIXED_DEC;
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  maybe_null= 0;
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  DBUG_VOID_RETURN;
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}


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/*
  Set decimal parameter value from string.

  SYNOPSIS
    set_decimal()
      str    - character string
      length - string length

  NOTE
    as we use character strings to send decimal values in
    binary protocol, we use str2my_decimal to convert it to
    internal decimal value.
*/
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void Item_param::set_decimal(const char *str, ulong length)
{
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  char *end;
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  DBUG_ENTER("Item_param::set_decimal");

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  end= (char*) str+length;
  str2my_decimal(E_DEC_FATAL_ERROR, str, &decimal_value, &end);
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  state= DECIMAL_VALUE;
  decimals= decimal_value.frac;
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  max_length= my_decimal_precision_to_length(decimal_value.precision(),
                                             decimals, unsigned_flag);
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  maybe_null= 0;
  DBUG_VOID_RETURN;
}


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/*
  Set parameter value from TIME value.

  SYNOPSIS
    set_time()
      tm             - datetime value to set (time_type is ignored)
      type           - type of datetime value
      max_length_arg - max length of datetime value as string

  NOTE
    If we value to be stored is not normalized, zero value will be stored
    instead and proper warning will be produced. This function relies on
    the fact that even wrong value sent over binary protocol fits into
    MAX_DATE_STRING_REP_LENGTH buffer.
*/
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void Item_param::set_time(TIME *tm, timestamp_type type, uint32 max_length_arg)
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{ 
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  DBUG_ENTER("Item_param::set_time");
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  value.time= *tm;
  value.time.time_type= type;
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  if (value.time.year > 9999 || value.time.month > 12 ||
      value.time.day > 31 ||
      type != MYSQL_TIMESTAMP_TIME && value.time.hour > 23 ||
      value.time.minute > 59 || value.time.second > 59)
  {
    char buff[MAX_DATE_STRING_REP_LENGTH];
    uint length= my_TIME_to_str(&value.time, buff);
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    make_truncated_value_warning(current_thd, buff, length, type, 0);
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    set_zero_time(&value.time, MYSQL_TIMESTAMP_ERROR);
  }

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  state= TIME_VALUE;
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  maybe_null= 0;
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  max_length= max_length_arg;
  decimals= 0;
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  DBUG_VOID_RETURN;
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}

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bool Item_param::set_str(const char *str, ulong length)
{
  DBUG_ENTER("Item_param::set_str");
  /*
    Assign string with no conversion: data is converted only after it's
    been written to the binary log.
  */
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  uint dummy_errors;
  if (str_value.copy(str, length, &my_charset_bin, &my_charset_bin,
                     &dummy_errors))
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    DBUG_RETURN(TRUE);
  state= STRING_VALUE;
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  max_length= length;
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  maybe_null= 0;
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  /* max_length and decimals are set after charset conversion */
  /* sic: str may be not null-terminated, don't add DBUG_PRINT here */
  DBUG_RETURN(FALSE);
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}


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bool Item_param::set_longdata(const char *str, ulong length)
{
  DBUG_ENTER("Item_param::set_longdata");

  /*
    If client character set is multibyte, end of long data packet
    may hit at the middle of a multibyte character.  Additionally,
    if binary log is open we must write long data value to the
    binary log in character set of client. This is why we can't
    convert long data to connection character set as it comes
    (here), and first have to concatenate all pieces together,
    write query to the binary log and only then perform conversion.
  */
  if (str_value.append(str, length, &my_charset_bin))
    DBUG_RETURN(TRUE);
  state= LONG_DATA_VALUE;
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  maybe_null= 0;
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  DBUG_RETURN(FALSE);
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}


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/*
  Set parameter value from user variable value.

  SYNOPSIS
   set_from_user_var
     thd   Current thread
     entry User variable structure (NULL means use NULL value)

  RETURN
    0 OK
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    1 Out of memory
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*/

bool Item_param::set_from_user_var(THD *thd, const user_var_entry *entry)
{
  DBUG_ENTER("Item_param::set_from_user_var");
  if (entry && entry->value)
  {
    item_result_type= entry->type;
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    switch (entry->type) {
    case REAL_RESULT:
      set_double(*(double*)entry->value);
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      item_type= Item::REAL_ITEM;
      item_result_type= REAL_RESULT;
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      break;
    case INT_RESULT:
      set_int(*(longlong*)entry->value, 21);
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      item_type= Item::INT_ITEM;
      item_result_type= INT_RESULT;
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      break;
    case STRING_RESULT:
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    {
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      CHARSET_INFO *fromcs= entry->collation.collation;
      CHARSET_INFO *tocs= thd->variables.collation_connection;
      uint32 dummy_offset;

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      value.cs_info.character_set_of_placeholder= fromcs;
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      /*
        Setup source and destination character sets so that they
        are different only if conversion is necessary: this will
        make later checks easier.
      */
      value.cs_info.final_character_set_of_str_value=
        String::needs_conversion(0, fromcs, tocs, &dummy_offset) ?
        tocs : fromcs;
      /*
        Exact value of max_length is not known unless data is converted to
        charset of connection, so we have to set it later.
      */
      item_type= Item::STRING_ITEM;
      item_result_type= STRING_RESULT;

      if (set_str((const char *)entry->value, entry->length))
        DBUG_RETURN(1);
      break;
    }
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    case DECIMAL_RESULT:
    {
      const my_decimal *ent_value= (const my_decimal *)entry->value;
      my_decimal2decimal(ent_value, &decimal_value);
      state= DECIMAL_VALUE;
      decimals= ent_value->frac;
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      max_length= my_decimal_precision_to_length(ent_value->precision(),
                                                 decimals, unsigned_flag);
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      break;
    }
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    default:
      DBUG_ASSERT(0);
      set_null();
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    }
  }
  else
    set_null();

  DBUG_RETURN(0);
}

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/*
    Resets parameter after execution.
  
  SYNOPSIS
     Item_param::reset()
 
  NOTES
    We clear null_value here instead of setting it in set_* methods, 
    because we want more easily handle case for long data.
*/

void Item_param::reset()
2491
{
2492
  DBUG_ENTER("Item_param::reset");
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  /* Shrink string buffer if it's bigger than max possible CHAR column */
  if (str_value.alloced_length() > MAX_CHAR_WIDTH)
    str_value.free();
  else
    str_value.length(0);
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  str_value_ptr.length(0);
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  /*
2500
    We must prevent all charset conversions until data has been written
2501
    to the binary log.
2502 2503
  */
  str_value.set_charset(&my_charset_bin);
2504
  collation.set(&my_charset_bin, DERIVATION_COERCIBLE);
2505
  state= NO_VALUE;
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  maybe_null= 1;
  null_value= 0;
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  /*
    Don't reset item_type to PARAM_ITEM: it's only needed to guard
    us from item optimizations at prepare stage, when item doesn't yet
    contain a literal of some kind.
    In all other cases when this object is accessed its value is
    set (this assumption is guarded by 'state' and
    DBUG_ASSERTS(state != NO_VALUE) in all Item_param::get_*
    methods).
  */
2517
  DBUG_VOID_RETURN;
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}


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int Item_param::save_in_field(Field *field, bool no_conversions)
2522 2523
{
  field->set_notnull();
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  switch (state) {
  case INT_VALUE:
2527
    return field->store(value.integer, unsigned_flag);
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  case REAL_VALUE:
    return field->store(value.real);
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  case DECIMAL_VALUE:
    return field->store_decimal(&decimal_value);
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  case TIME_VALUE:
    field->store_time(&value.time, value.time.time_type);
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    return 0;
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  case STRING_VALUE:
  case LONG_DATA_VALUE:
    return field->store(str_value.ptr(), str_value.length(),
                        str_value.charset());
  case NULL_VALUE:
2540
    return set_field_to_null_with_conversions(field, no_conversions);
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  case NO_VALUE:
  default:
    DBUG_ASSERT(0);
2544
  }
2545
  return 1;
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}

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bool Item_param::get_time(TIME *res)
{
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  if (state == TIME_VALUE)
  {
    *res= value.time;
    return 0;
  }
  /*
    If parameter value isn't supplied assertion will fire in val_str()
    which is called from Item::get_time().
  */
  return Item::get_time(res);
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}
2562

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bool Item_param::get_date(TIME *res, uint fuzzydate)
{
  if (state == TIME_VALUE)
  {
    *res= value.time;
    return 0;
  }
  return Item::get_date(res, fuzzydate);
}


2575
double Item_param::val_real()
2576
{
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  switch (state) {
  case REAL_VALUE:
    return value.real;
  case INT_VALUE:
    return (double) value.integer;
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  case DECIMAL_VALUE:
  {
    double result;
    my_decimal2double(E_DEC_FATAL_ERROR, &decimal_value, &result);
    return result;
  }
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  case STRING_VALUE:
  case LONG_DATA_VALUE:
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  {
    int dummy_err;
    char *end_not_used;
    return my_strntod(str_value.charset(), (char*) str_value.ptr(),
                      str_value.length(), &end_not_used, &dummy_err);
  }
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  case TIME_VALUE:
    /*
      This works for example when user says SELECT ?+0.0 and supplies
      time value for the placeholder.
    */
2601
    return ulonglong2double(TIME_to_ulonglong(&value.time));
2602
  case NULL_VALUE:
2603
    return 0.0;
2604
  default:
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    DBUG_ASSERT(0);
2606
  }
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  return 0.0;
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} 

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longlong Item_param::val_int() 
{ 
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  switch (state) {
  case REAL_VALUE:
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    return (longlong) rint(value.real);
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  case INT_VALUE:
    return value.integer;
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  case DECIMAL_VALUE:
  {
    longlong i;
    my_decimal2int(E_DEC_FATAL_ERROR, &decimal_value, unsigned_flag, &i);
    return i;
  }
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  case STRING_VALUE:
  case LONG_DATA_VALUE:
    {
      int dummy_err;
      return my_strntoll(str_value.charset(), str_value.ptr(),
                         str_value.length(), 10, (char**) 0, &dummy_err);
    }
  case TIME_VALUE:
    return (longlong) TIME_to_ulonglong(&value.time);
  case NULL_VALUE:
    return 0; 
2635
  default:
2636
    DBUG_ASSERT(0);
2637
  }
2638
  return 0;
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}

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my_decimal *Item_param::val_decimal(my_decimal *dec)
{
  switch (state) {
  case DECIMAL_VALUE:
    return &decimal_value;
  case REAL_VALUE:
    double2my_decimal(E_DEC_FATAL_ERROR, value.real, dec);
    return dec;
  case INT_VALUE:
    int2my_decimal(E_DEC_FATAL_ERROR, value.integer, unsigned_flag, dec);
    return dec;
  case STRING_VALUE:
  case LONG_DATA_VALUE:
    string2my_decimal(E_DEC_FATAL_ERROR, &str_value, dec);
    return dec;
  case TIME_VALUE:
  {
    longlong i= (longlong) TIME_to_ulonglong(&value.time);
    int2my_decimal(E_DEC_FATAL_ERROR, i, 0, dec);
    return dec;
  }
  case NULL_VALUE:
    return 0; 
  default:
    DBUG_ASSERT(0);
  }
  return 0;
}


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String *Item_param::val_str(String* str) 
{ 
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  switch (state) {
  case STRING_VALUE:
  case LONG_DATA_VALUE:
2677
    return &str_value_ptr;
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  case REAL_VALUE:
    str->set(value.real, NOT_FIXED_DEC, &my_charset_bin);
    return str;
  case INT_VALUE:
    str->set(value.integer, &my_charset_bin);
2683
    return str;
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  case DECIMAL_VALUE:
    if (my_decimal2string(E_DEC_FATAL_ERROR, &decimal_value,
                          0, 0, 0, str) <= 1)
      return str;
    return NULL;
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  case TIME_VALUE:
  {
2691
    if (str->reserve(MAX_DATE_STRING_REP_LENGTH))
2692
      break;
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    str->length((uint) my_TIME_to_str(&value.time, (char*) str->ptr()));
    str->set_charset(&my_charset_bin);
2695
    return str;
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  }
  case NULL_VALUE:
    return NULL; 
2699
  default:
2700
    DBUG_ASSERT(0);
2701
  }
2702
  return str;
2703
}
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/*
  Return Param item values in string format, for generating the dynamic 
  query used in update/binary logs
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  TODO: change interface and implementation to fill log data in place
  and avoid one more memcpy/alloc between str and log string.
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*/

2712
const String *Item_param::query_val_str(String* str) const
2713
{
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  switch (state) {
  case INT_VALUE:
    str->set(value.integer, &my_charset_bin);
    break;
  case REAL_VALUE:
    str->set(value.real, NOT_FIXED_DEC, &my_charset_bin);
    break;
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  case DECIMAL_VALUE:
    if (my_decimal2string(E_DEC_FATAL_ERROR, &decimal_value,
                          0, 0, 0, str) > 1)
      return &my_null_string;
    break;
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  case TIME_VALUE:
2727
    {
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      char *buf, *ptr;
      str->length(0);
      /*
        TODO: in case of error we need to notify replication
        that binary log contains wrong statement 
      */
2734
      if (str->reserve(MAX_DATE_STRING_REP_LENGTH+3))
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        break; 

      /* Create date string inplace */
      buf= str->c_ptr_quick();
      ptr= buf;
      *ptr++= '\'';
2741
      ptr+= (uint) my_TIME_to_str(&value.time, ptr);
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      *ptr++= '\'';
      str->length((uint32) (ptr - buf));
      break;
2745
    }
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  case STRING_VALUE:
  case LONG_DATA_VALUE:
2748
    {
2749
      str->length(0);
2750
      append_query_string(value.cs_info.character_set_client, &str_value, str);
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      break;
2752
    }
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  case NULL_VALUE:
    return &my_null_string;
  default:
    DBUG_ASSERT(0);
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  }
  return str;
}
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/*
  Convert string from client character set to the character set of
  connection.
*/

bool Item_param::convert_str_value(THD *thd)
{
  bool rc= FALSE;
  if (state == STRING_VALUE || state == LONG_DATA_VALUE)
  {
    /*
      Check is so simple because all charsets were set up properly
      in setup_one_conversion_function, where typecode of
      placeholder was also taken into account: the variables are different
      here only if conversion is really necessary.
    */
    if (value.cs_info.final_character_set_of_str_value !=
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        value.cs_info.character_set_of_placeholder)
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    {
      rc= thd->convert_string(&str_value,
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                              value.cs_info.character_set_of_placeholder,
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                              value.cs_info.final_character_set_of_str_value);
    }
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    else
      str_value.set_charset(value.cs_info.final_character_set_of_str_value);
    /* Here str_value is guaranteed to be in final_character_set_of_str_value */

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    max_length= str_value.length();
    decimals= 0;
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    /*
      str_value_ptr is returned from val_str(). It must be not alloced
      to prevent it's modification by val_str() invoker.
    */
    str_value_ptr.set(str_value.ptr(), str_value.length(),
                      str_value.charset());
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    /* Synchronize item charset with value charset */
    collation.set(str_value.charset(), DERIVATION_COERCIBLE);
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  }
  return rc;
}

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bool Item_param::basic_const_item() const
{
  if (state == NO_VALUE || state == TIME_VALUE)
    return FALSE;
  return TRUE;
}

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Item *
Item_param::new_item()
{
  /* see comments in the header file */
  switch (state) {
  case NULL_VALUE:
    return new Item_null(name);
  case INT_VALUE:
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    return (unsigned_flag ?
            new Item_uint(name, value.integer, max_length) :
            new Item_int(name, value.integer, max_length));
2823
  case REAL_VALUE:
2824
    return new Item_float(name, value.real, decimals, max_length);
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  case STRING_VALUE:
  case LONG_DATA_VALUE:
    return new Item_string(name, str_value.c_ptr_quick(), str_value.length(),
                           str_value.charset());
  case TIME_VALUE:
    break;
  case NO_VALUE:
  default:
    DBUG_ASSERT(0);
  };
  return 0;
}


bool
Item_param::eq(const Item *arg, bool binary_cmp) const
{
  Item *item;
  if (!basic_const_item() || !arg->basic_const_item() || arg->type() != type())
    return FALSE;
  /*
    We need to cast off const to call val_int(). This should be OK for
    a basic constant.
  */
  item= (Item*) arg;

  switch (state) {
  case NULL_VALUE:
    return TRUE;
  case INT_VALUE:
    return value.integer == item->val_int() &&
           unsigned_flag == item->unsigned_flag;
  case REAL_VALUE:
2858
    return value.real == item->val_real();
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  case STRING_VALUE:
  case LONG_DATA_VALUE:
    if (binary_cmp)
      return !stringcmp(&str_value, &item->str_value);
    return !sortcmp(&str_value, &item->str_value, collation.collation);
  default:
    break;
  }
  return FALSE;
}

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/* End of Item_param related */

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void Item_param::print(String *str)
{
  if (state == NO_VALUE)
  {
    str->append('?');
  }
  else
  {
2880
    char buffer[STRING_BUFFER_USUAL_SIZE];
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    String tmp(buffer, sizeof(buffer), &my_charset_bin);
    const String *res;
    res= query_val_str(&tmp);
    str->append(*res);
  }
}


/****************************************************************************
  Item_copy_string
****************************************************************************/
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void Item_copy_string::copy()
{
  String *res=item->val_str(&str_value);
  if (res && res != &str_value)
    str_value.copy(*res);
  null_value=item->null_value;
}

/* ARGSUSED */
String *Item_copy_string::val_str(String *str)
{
2904
  // Item_copy_string is used without fix_fields call
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  if (null_value)
    return (String*) 0;
  return &str_value;
}

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my_decimal *Item_copy_string::val_decimal(my_decimal *decimal_value)
{
  // Item_copy_string is used without fix_fields call
  if (null_value)
    return 0;
  string2my_decimal(E_DEC_FATAL_ERROR, &str_value, decimal_value);
  return (decimal_value);
}



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int Item_copy_string::save_in_field(Field *field, bool no_conversions)
{
  if (null_value)
    return set_field_to_null(field);
  field->set_notnull();
  return field->store(str_value.ptr(),str_value.length(),
		      collation.collation);
}

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/*
2932
  Functions to convert item to field (for send_fields)
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*/

/* ARGSUSED */
2936
bool Item::fix_fields(THD *thd, Item **ref)
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{
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  // We do not check fields which are fixed during construction
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  DBUG_ASSERT(fixed == 0 || basic_const_item());
2941
  fixed= 1;
2942
  return FALSE;
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}

2945
double Item_ref_null_helper::val_real()
2946
{
2947
  DBUG_ASSERT(fixed == 1);
2948
  double tmp= (*ref)->val_result();
2949
  owner->was_null|= null_value= (*ref)->null_value;
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  return tmp;
}
2952 2953


2954 2955
longlong Item_ref_null_helper::val_int()
{
2956
  DBUG_ASSERT(fixed == 1);
2957
  longlong tmp= (*ref)->val_int_result();
2958
  owner->was_null|= null_value= (*ref)->null_value;
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  return tmp;
}
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my_decimal *Item_ref_null_helper::val_decimal(my_decimal *decimal_value)
{
  DBUG_ASSERT(fixed == 1);
  my_decimal *val= (*ref)->val_decimal_result(decimal_value);
  owner->was_null|= null_value= (*ref)->null_value;
  return val;
}


bool Item_ref_null_helper::val_bool()
{
  DBUG_ASSERT(fixed == 1);
  bool val= (*ref)->val_bool_result();
  owner->was_null|= null_value= (*ref)->null_value;
  return val;
}


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String* Item_ref_null_helper::val_str(String* s)
{
2983
  DBUG_ASSERT(fixed == 1);
2984
  String* tmp= (*ref)->str_result(s);
2985
  owner->was_null|= null_value= (*ref)->null_value;
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  return tmp;
}
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2990
bool Item_ref_null_helper::get_date(TIME *ltime, uint fuzzydate)
2991 2992 2993
{  
  return (owner->was_null|= null_value= (*ref)->get_date(ltime, fuzzydate));
}
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/*
2997
  Mark item and SELECT_LEXs as dependent if item was resolved in outer SELECT
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  SYNOPSIS
    mark_as_dependent()
3001
    thd - thread handler
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    last - select from which current item depend
    current  - current select
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    resolved_item - item which was resolved in outer SELECT(for warning)
    mark_item - item which should be marked (can be differ in case of
                substitution)
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*/

3009
static void mark_as_dependent(THD *thd, SELECT_LEX *last, SELECT_LEX *current,
3010
                              Item_ident *resolved_item,
3011
                              Item_ident *mark_item)
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{
3013 3014 3015 3016
  const char *db_name= (resolved_item->db_name ?
                        resolved_item->db_name : "");
  const char *table_name= (resolved_item->table_name ?
                           resolved_item->table_name : "");
3017
  /* store pointer on SELECT_LEX from which item is dependent */
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  if (mark_item)
    mark_item->depended_from= last;
3020
  current->mark_as_dependent(last);
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  if (thd->lex->describe & DESCRIBE_EXTENDED)
3022 3023 3024
  {
    char warn_buff[MYSQL_ERRMSG_SIZE];
    sprintf(warn_buff, ER(ER_WARN_FIELD_RESOLVED),
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            db_name, (db_name[0] ? "." : ""),
            table_name, (table_name [0] ? "." : ""),
3027
            resolved_item->field_name,
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	    current->select_number, last->select_number);
    push_warning(thd, MYSQL_ERROR::WARN_LEVEL_NOTE,
		 ER_WARN_FIELD_RESOLVED, warn_buff);
  }
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}


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/*
  Mark range of selects and resolved identifier (field/reference) item as
  dependent

  SYNOPSIS
    mark_select_range_as_dependent()
    thd           - thread handler
    last_select   - select where resolved_item was resolved
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    current_sel   - current select (select where resolved_item was placed)
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    found_field   - field which was found during resolving
    found_item    - Item which was found during resolving (if resolved
                    identifier belongs to VIEW)
    resolved_item - Identifier which was resolved

  NOTE:
    We have to mark all items between current_sel (including) and
    last_select (excluding) as dependend (select before last_select should
    be marked with actual table mask used by resolved item, all other with
    OUTER_REF_TABLE_BIT) and also write dependence information to Item of
    resolved identifier.
*/

void mark_select_range_as_dependent(THD *thd,
                                    SELECT_LEX *last_select,
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                                    SELECT_LEX *current_sel,
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                                    Field *found_field, Item *found_item,
                                    Item_ident *resolved_item)
{
  /*
    Go from current SELECT to SELECT where field was resolved (it
    have to be reachable from current SELECT, because it was already
    done once when we resolved this field and cached result of
    resolving)
  */
  SELECT_LEX *previous_select= current_sel;
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  for (; previous_select->outer_select() != last_select;
       previous_select= previous_select->outer_select())
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  {
    Item_subselect *prev_subselect_item=
      previous_select->master_unit()->item;
    prev_subselect_item->used_tables_cache|= OUTER_REF_TABLE_BIT;
    prev_subselect_item->const_item_cache= 0;
  }
  {
    Item_subselect *prev_subselect_item=
      previous_select->master_unit()->item;
    Item_ident *dependent= resolved_item;
    if (found_field == view_ref_found)
    {
      Item::Type type= found_item->type();
      prev_subselect_item->used_tables_cache|=
        found_item->used_tables();
      dependent= ((type == Item::REF_ITEM || type == Item::FIELD_ITEM) ?
                  (Item_ident*) found_item :
                  0);
    }
    else
      prev_subselect_item->used_tables_cache|=
        found_field->table->map;
    prev_subselect_item->const_item_cache= 0;
    mark_as_dependent(thd, last_select, current_sel, resolved_item,
                      dependent);
  }
}
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/*
  Search a GROUP BY clause for a field with a certain name.

  SYNOPSIS
    find_field_in_group_list()
    find_item  the item being searched for
    group_list GROUP BY clause

  DESCRIPTION
    Search the GROUP BY list for a column named as find_item. When searching
    preference is given to columns that are qualified with the same table (and
    database) name as the one being searched for.

  RETURN
    - the found item on success
    - NULL if find_item is not in group_list
*/

static Item** find_field_in_group_list(Item *find_item, ORDER *group_list)
{
  const char *db_name;
  const char *table_name;
  const char *field_name;
  ORDER      *found_group= NULL;
  int         found_match_degree= 0;
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  Item_ident *cur_field;
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  int         cur_match_degree= 0;
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  char        name_buff[NAME_LEN+1];
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  if (find_item->type() == Item::FIELD_ITEM ||
      find_item->type() == Item::REF_ITEM)
  {
    db_name=    ((Item_ident*) find_item)->db_name;
    table_name= ((Item_ident*) find_item)->table_name;
    field_name= ((Item_ident*) find_item)->field_name;
  }
  else
    return NULL;

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  if (db_name && lower_case_table_names)
  {
    /* Convert database to lower case for comparison */
    strmake(name_buff, db_name, sizeof(name_buff)-1);
    my_casedn_str(files_charset_info, name_buff);
    db_name= name_buff;
  }

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  DBUG_ASSERT(field_name != 0);
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  for (ORDER *cur_group= group_list ; cur_group ; cur_group= cur_group->next)
  {
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    if ((*(cur_group->item))->real_item()->type() == Item::FIELD_ITEM)
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    {
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      cur_field= (Item_ident*) *cur_group->item;
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      cur_match_degree= 0;
      
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      DBUG_ASSERT(cur_field->field_name != 0);
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      if (!my_strcasecmp(system_charset_info,
                         cur_field->field_name, field_name))
        ++cur_match_degree;
      else
        continue;

      if (cur_field->table_name && table_name)
      {
        /* If field_name is qualified by a table name. */
        if (strcmp(cur_field->table_name, table_name))
          /* Same field names, different tables. */
          return NULL;

        ++cur_match_degree;
        if (cur_field->db_name && db_name)
        {
          /* If field_name is also qualified by a database name. */
          if (strcmp(cur_field->db_name, db_name))
            /* Same field names, different databases. */
            return NULL;
          ++cur_match_degree;
        }
      }

      if (cur_match_degree > found_match_degree)
      {
        found_match_degree= cur_match_degree;
        found_group= cur_group;
      }
      else if (found_group && (cur_match_degree == found_match_degree) &&
               ! (*(found_group->item))->eq(cur_field, 0))
      {
        /*
          If the current resolve candidate matches equally well as the current
          best match, they must reference the same column, otherwise the field
          is ambiguous.
        */
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        my_error(ER_NON_UNIQ_ERROR, MYF(0),
                 find_item->full_name(), current_thd->where);
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        return NULL;
      }
    }
  }

  if (found_group)
    return found_group->item;
  else
    return NULL;
}


/*
  Resolve a column reference in a sub-select.

  SYNOPSIS
    resolve_ref_in_select_and_group()
    thd     current thread
    ref     column reference being resolved
    select  the sub-select that ref is resolved against

  DESCRIPTION
    Resolve a column reference (usually inside a HAVING clause) against the
    SELECT and GROUP BY clauses of the query described by 'select'. The name
    resolution algorithm searches both the SELECT and GROUP BY clauses, and in
    case of a name conflict prefers GROUP BY column names over SELECT names. If
    both clauses contain different fields with the same names, a warning is
    issued that name of 'ref' is ambiguous. We extend ANSI SQL in that when no
    GROUP BY column is found, then a HAVING name is resolved as a possibly
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    derived SELECT column. This extension is allowed only if the
    MODE_ONLY_FULL_GROUP_BY sql mode isn't enabled.
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  NOTES
    The resolution procedure is:
    - Search for a column or derived column named col_ref_i [in table T_j]
      in the SELECT clause of Q.
    - Search for a column named col_ref_i [in table T_j]
      in the GROUP BY clause of Q.
    - If found different columns with the same name in GROUP BY and SELECT
      - issue a warning and return the GROUP BY column,
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      - otherwise
        - if the MODE_ONLY_FULL_GROUP_BY mode is enabled return error
        - else return the found SELECT column.
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  RETURN
    NULL - there was an error, and the error was already reported
    not_found_item - the item was not resolved, no error was reported
    resolved item - if the item was resolved
*/

static Item**
resolve_ref_in_select_and_group(THD *thd, Item_ident *ref, SELECT_LEX *select)
{
  Item **group_by_ref= NULL;
  Item **select_ref= NULL;
  ORDER *group_list= (ORDER*) select->group_list.first;
  bool ambiguous_fields= FALSE;
  uint counter;
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  bool not_used;
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  /*
    Search for a column or derived column named as 'ref' in the SELECT
    clause of the current select.
  */
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  if (!(select_ref= find_item_in_list(ref, *(select->get_item_list()),
                                      &counter, REPORT_EXCEPT_NOT_FOUND,
                                      &not_used)))
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    return NULL; /* Some error occurred. */

  /* If this is a non-aggregated field inside HAVING, search in GROUP BY. */
  if (select->having_fix_field && !ref->with_sum_func && group_list)
  {
    group_by_ref= find_field_in_group_list(ref, group_list);
    
    /* Check if the fields found in SELECT and GROUP BY are the same field. */
    if (group_by_ref && (select_ref != not_found_item) &&
        !((*group_by_ref)->eq(*select_ref, 0)))
    {
      ambiguous_fields= TRUE;
      push_warning_printf(thd, MYSQL_ERROR::WARN_LEVEL_WARN, ER_NON_UNIQ_ERROR,
                          ER(ER_NON_UNIQ_ERROR), ref->full_name(),
                          current_thd->where);

    }
  }

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  if (thd->variables.sql_mode & MODE_ONLY_FULL_GROUP_BY &&
      select_ref != not_found_item && !group_by_ref)
  {
    /*
      Report the error if fields was found only in the SELECT item list and
      the strict mode is enabled.
    */
    my_error(ER_NON_GROUPING_FIELD_USED, MYF(0),
             ref->name, "HAVING");
    return NULL;
  }
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  if (select_ref != not_found_item || group_by_ref)
  {
    if (select_ref != not_found_item && !ambiguous_fields)
    {
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      DBUG_ASSERT(*select_ref != 0);
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      if (!select->ref_pointer_array[counter])
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      {
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        my_error(ER_ILLEGAL_REFERENCE, MYF(0),
                 ref->name, "forward reference in item list");
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        return NULL;
      }
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      DBUG_ASSERT((*select_ref)->fixed);
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      return (select->ref_pointer_array + counter);
    }
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    if (group_by_ref)
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      return group_by_ref;
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    DBUG_ASSERT(FALSE);
    return NULL; /* So there is no compiler warning. */
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  }
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  return (Item**) not_found_item;
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}


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/*
  Resolve the name of an outer select column reference.

  SYNOPSIS
    Item_field::fix_outer_field()
    thd        [in]      current thread
    from_field [in/out]  found field reference or (Field*)not_found_field
    reference  [in/out]  view column if this item was resolved to a view column

  DESCRIPTION
    The method resolves the column reference represented by 'this' as a column
    present in outer selects that contain current select.

  NOTES
    This is the inner loop of Item_field::fix_fields:

      for each outer query Q_k beginning from the inner-most one
      {
        search for a column or derived column named col_ref_i
        [in table T_j] in the FROM clause of Q_k;

        if such a column is not found
          Search for a column or derived column named col_ref_i
          [in table T_j] in the SELECT and GROUP clauses of Q_k.
      }

  IMPLEMENTATION
    In prepared statements, because of cache, find_field_in_tables()
    can resolve fields even if they don't belong to current context.
    In this case this method only finds appropriate context and marks
    current select as dependent. The found reference of field should be
    provided in 'from_field'.

  RETURN
     1 - column succefully resolved and fix_fields() should continue.
     0 - column fully fixed and fix_fields() should return FALSE
    -1 - error occured
*/
int
Item_field::fix_outer_field(THD *thd, Field **from_field, Item **reference)
{
  enum_parsing_place place= NO_MATTER;
  bool field_found= (*from_field != not_found_field);
  bool upward_lookup= FALSE;

  /*
    If there are outer contexts (outer selects, but current select is
    not derived table or view) try to resolve this reference in the
    outer contexts.

    We treat each subselect as a separate namespace, so that different
    subselects may contain columns with the same names. The subselects
    are searched starting from the innermost.
  */
  Name_resolution_context *last_checked_context= context;
  Item **ref= (Item **) not_found_item;
  Name_resolution_context *outer_context= context->outer_context;
  for (;
       outer_context;
       outer_context= outer_context->outer_context)
  {
    SELECT_LEX *select= outer_context->select_lex;
    Item_subselect *prev_subselect_item=
      last_checked_context->select_lex->master_unit()->item;
    last_checked_context= outer_context;
    upward_lookup= TRUE;

    place= prev_subselect_item->parsing_place;
    /*
      If outer_field is set, field was already found by first call
      to find_field_in_tables(). Only need to find appropriate context.
    */
    if (field_found && outer_context->select_lex !=
        cached_table->select_lex)
      continue;
    /*
      In case of a view, find_field_in_tables() writes the pointer to
      the found view field into '*reference', in other words, it
      substitutes this Item_field with the found expression.
    */
    if (field_found || (*from_field= find_field_in_tables(thd, this,
                                          outer_context->
                                            first_name_resolution_table,
                                          outer_context->
                                            last_name_resolution_table,
                                          reference,
                                          IGNORE_EXCEPT_NON_UNIQUE,
                                          TRUE, TRUE)) !=
        not_found_field)
    {
      if (*from_field)
      {
        if (*from_field != view_ref_found)
        {
          prev_subselect_item->used_tables_cache|= (*from_field)->table->map;
          prev_subselect_item->const_item_cache= 0;
          if (thd->lex->in_sum_func &&
              thd->lex->in_sum_func->nest_level == 
              thd->lex->current_select->nest_level)
          {
            Item::Type type= (*reference)->type();
            set_if_bigger(thd->lex->in_sum_func->max_arg_level,
                          select->nest_level);
            set_field(*from_field);
            fixed= 1;
            mark_as_dependent(thd, last_checked_context->select_lex,
                              context->select_lex, this,
                              ((type == REF_ITEM || type == FIELD_ITEM) ?
                               (Item_ident*) (*reference) : 0));
            return 0;
          }
        }
        else
        {
          Item::Type type= (*reference)->type();
          prev_subselect_item->used_tables_cache|=
            (*reference)->used_tables();
          prev_subselect_item->const_item_cache&=
            (*reference)->const_item();
          mark_as_dependent(thd, last_checked_context->select_lex,
                            context->select_lex, this,
                            ((type == REF_ITEM || type == FIELD_ITEM) ?
                             (Item_ident*) (*reference) :
                             0));
          /*
            A reference to a view field had been found and we
            substituted it instead of this Item (find_field_in_tables
            does it by assigning the new value to *reference), so now
            we can return from this function.
          */
          return 0;
        }
      }
      break;
    }

    /* Search in SELECT and GROUP lists of the outer select. */
    if (outer_context->resolve_in_select_list)
    {
      if (!(ref= resolve_ref_in_select_and_group(thd, this, select)))
        return -1; /* Some error occurred (e.g. ambiguous names). */
      if (ref != not_found_item)
      {
        DBUG_ASSERT(*ref && (*ref)->fixed);
        prev_subselect_item->used_tables_cache|= (*ref)->used_tables();
        prev_subselect_item->const_item_cache&= (*ref)->const_item();
        break;
      }
    }

    /*
      Reference is not found in this select => this subquery depend on
      outer select (or we just trying to find wrong identifier, in this
      case it does not matter which used tables bits we set)
    */
    prev_subselect_item->used_tables_cache|= OUTER_REF_TABLE_BIT;
    prev_subselect_item->const_item_cache= 0;
  }

  DBUG_ASSERT(ref != 0);
  if (!*from_field)
    return -1;
  if (ref == not_found_item && *from_field == not_found_field)
  {
    if (upward_lookup)
    {
      // We can't say exactly what absent table or field
      my_error(ER_BAD_FIELD_ERROR, MYF(0), full_name(), thd->where);
    }
    else
    {
      /* Call find_field_in_tables only to report the error */
      find_field_in_tables(thd, this,
                           context->first_name_resolution_table,
                           context->last_name_resolution_table,
                           reference, REPORT_ALL_ERRORS,
                           !any_privileges &&
                           TRUE, TRUE);
    }
    return -1;
  }
  else if (ref != not_found_item)
  {
    Item *save;
    Item_ref *rf;

    /* Should have been checked in resolve_ref_in_select_and_group(). */
    DBUG_ASSERT(*ref && (*ref)->fixed);
    /*
      Here, a subset of actions performed by Item_ref::set_properties
      is not enough. So we pass ptr to NULL into Item_[direct]_ref
      constructor, so no initialization is performed, and call 
      fix_fields() below.
    */
    save= *ref;
    *ref= NULL;                             // Don't call set_properties()
    rf= (place == IN_HAVING ?
         new Item_ref(context, ref, (char*) table_name,
                      (char*) field_name) :
         new Item_direct_ref(context, ref, (char*) table_name,
                             (char*) field_name));
    *ref= save;
    if (!rf)
      return -1;
    thd->change_item_tree(reference, rf);
    /*
      rf is Item_ref => never substitute other items (in this case)
      during fix_fields() => we can use rf after fix_fields()
    */
    DBUG_ASSERT(!rf->fixed);                // Assured by Item_ref()
    if (rf->fix_fields(thd, reference) || rf->check_cols(1))
      return -1;

    mark_as_dependent(thd, last_checked_context->select_lex,
                      context->select_lex, this,
                      rf);
    return 0;
  }
  else
  {
    mark_as_dependent(thd, last_checked_context->select_lex,
                      context->select_lex,
                      this, this);
    if (last_checked_context->select_lex->having_fix_field)
    {
      Item_ref *rf;
      rf= new Item_ref(context,
                       (cached_table->db[0] ? cached_table->db : 0),
                       (char*) cached_table->alias, (char*) field_name);
      if (!rf)
        return -1;
      thd->change_item_tree(reference, rf);
      /*
        rf is Item_ref => never substitute other items (in this case)
        during fix_fields() => we can use rf after fix_fields()
      */
      DBUG_ASSERT(!rf->fixed);                // Assured by Item_ref()
      if (rf->fix_fields(thd, reference) || rf->check_cols(1))
        return -1;
      return 0;
    }
  }
  return 1;
}


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/*
  Resolve the name of a column reference.

  SYNOPSIS
    Item_field::fix_fields()
    thd       [in]      current thread
    reference [in/out]  view column if this item was resolved to a view column

  DESCRIPTION
    The method resolves the column reference represented by 'this' as a column
    present in one of: FROM clause, SELECT clause, GROUP BY clause of a query
    Q, or in outer queries that contain Q.

  NOTES
    The name resolution algorithm used is (where [T_j] is an optional table
    name that qualifies the column name):

      resolve_column_reference([T_j].col_ref_i)
      {
        search for a column or derived column named col_ref_i
        [in table T_j] in the FROM clause of Q;

        if such a column is NOT found AND    // Lookup in outer queries.
           there are outer queries
        {
          for each outer query Q_k beginning from the inner-most one
          {
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            search for a column or derived column named col_ref_i
            [in table T_j] in the FROM clause of Q_k;
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            if such a column is not found
              Search for a column or derived column named col_ref_i
              [in table T_j] in the SELECT and GROUP clauses of Q_k.
          }
        }
      }

    Notice that compared to Item_ref::fix_fields, here we first search the FROM
    clause, and then we search the SELECT and GROUP BY clauses.

  RETURN
    TRUE  if error
    FALSE on success
*/

3611
bool Item_field::fix_fields(THD *thd, Item **reference)
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{
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  DBUG_ASSERT(fixed == 0);
3614
  if (!field)					// If field is not checked
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  {
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    Field *from_field= (Field *)not_found_field;
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    bool outer_fixed= false;
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    /*
      In case of view, find_field_in_tables() write pointer to view field
      expression to 'reference', i.e. it substitute that expression instead
      of this Item_field
    */
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    if ((from_field= find_field_in_tables(thd, this,
                                          context->first_name_resolution_table,
                                          context->last_name_resolution_table,
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                                          reference,
                                          IGNORE_EXCEPT_NON_UNIQUE,
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                                          !any_privileges,
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                                          TRUE)) ==
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	not_found_field)
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    {
3632
      int ret;
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      /* Look up in current select's item_list to find aliased fields */
      if (thd->lex->current_select->is_item_list_lookup)
      {
        uint counter;
        bool not_used;
        Item** res= find_item_in_list(this, thd->lex->current_select->item_list,
                                      &counter, REPORT_EXCEPT_NOT_FOUND,
                                      &not_used);
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        if (res != (Item **)not_found_item && (*res)->type() == Item::FIELD_ITEM)
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        {
          set_field((*((Item_field**)res))->field);
          return 0;
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        }
      }
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      if ((ret= fix_outer_field(thd, &from_field, reference)) < 0)
        goto error;
      else if (!ret)
        return FALSE;
      outer_fixed= TRUE;
3652
    }
3653
    else if (!from_field)
3654
      goto error;
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VIEW  
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    /*
      if it is not expression from merged VIEW we will set this field.

      We can leave expression substituted from view for next PS/SP rexecution
      (i.e. do not register this substitution for reverting on cleupup()
      (register_item_tree_changing())), because this subtree will be
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      fix_field'ed during setup_tables()->setup_underlying() (i.e. before
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      all other expressions of query, and references on tables which do
      not present in query will not make problems.

      Also we suppose that view can't be changed during PS/SP life.
    */
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    if (from_field == view_ref_found)
      return FALSE;

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    if (!outer_fixed && cached_table && cached_table->select_lex &&
          context->select_lex &&
          cached_table->select_lex != context->select_lex)
    {
      int ret;
      if ((ret= fix_outer_field(thd, &from_field, reference)) < 0)
        goto error;
      else if (!ret)
        return FALSE;
    }

3682
    set_field(from_field);
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3683 3684 3685 3686 3687
    if (thd->lex->in_sum_func &&
        thd->lex->in_sum_func->nest_level == 
        thd->lex->current_select->nest_level)
      set_if_bigger(thd->lex->in_sum_func->max_arg_level,
                    thd->lex->current_select->nest_level);
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3688
  }
3689
  else if (thd->set_query_id && field->query_id != thd->query_id)
3690 3691 3692 3693 3694
  {
    /* We only come here in unions */
    TABLE *table=field->table;
    field->query_id=thd->query_id;
    table->used_fields++;
3695
    table->used_keys.intersect(field->part_of_key);
3696
  }
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VIEW  
bell@sanja.is.com.ua committed
3697 3698 3699 3700 3701 3702 3703 3704 3705 3706 3707 3708
#ifndef NO_EMBEDDED_ACCESS_CHECKS
  if (any_privileges)
  {
    char *db, *tab;
    if (cached_table->view)
    {
      db= cached_table->view_db.str;
      tab= cached_table->view_name.str;
    }
    else
    {
      db= cached_table->db;
3709
      tab= cached_table->table_name;
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VIEW  
bell@sanja.is.com.ua committed
3710 3711 3712 3713 3714
    }
    if (!(have_privileges= (get_column_grant(thd, &field->table->grant,
                                             db, tab, field_name) &
                            VIEW_ANY_ACL)))
    {
3715
      my_error(ER_COLUMNACCESS_DENIED_ERROR, MYF(0),
3716 3717
               "ANY", thd->security_ctx->priv_user,
               thd->security_ctx->host_or_ip, field_name, tab);
3718
      goto error;
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VIEW  
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3719 3720 3721
    }
  }
#endif
3722
  fixed= 1;
3723
  return FALSE;
3724 3725 3726 3727

error:
  context->process_error(thd);
  return TRUE;
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3728 3729
}

3730 3731 3732 3733 3734 3735 3736 3737

Item *Item_field::safe_charset_converter(CHARSET_INFO *tocs)
{
  no_const_subst= 1;
  return Item::safe_charset_converter(tocs);
}


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3738 3739
void Item_field::cleanup()
{
3740
  DBUG_ENTER("Item_field::cleanup");
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3741
  Item_ident::cleanup();
3742 3743
  /*
    Even if this object was created by direct link to field in setup_wild()
3744
    it will be linked correctly next time by name of field and table alias.
3745 3746
    I.e. we can drop 'field'.
   */
3747
  field= result_field= 0;
3748
  null_value= FALSE;
3749
  DBUG_VOID_RETURN;
3750
}
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3751 3752 3753 3754 3755 3756 3757 3758 3759 3760 3761 3762 3763 3764 3765 3766 3767 3768 3769 3770 3771

/*
  Find a field among specified multiple equalities 

  SYNOPSIS
    find_item_equal()
    cond_equal   reference to list of multiple equalities where
                 the field (this object) is to be looked for
  
  DESCRIPTION
    The function first searches the field among multiple equalities
    of the current level (in the cond_equal->current_level list).
    If it fails, it continues searching in upper levels accessed
    through a pointer cond_equal->upper_levels.
    The search terminates as soon as a multiple equality containing 
    the field is found. 

  RETURN VALUES
    First Item_equal containing the field, if success
    0, otherwise
*/
3772 3773 3774 3775 3776 3777 3778 3779 3780 3781 3782 3783 3784 3785 3786 3787 3788 3789 3790 3791 3792
Item_equal *Item_field::find_item_equal(COND_EQUAL *cond_equal)
{
  Item_equal *item= 0;
  while (cond_equal)
  {
    List_iterator_fast<Item_equal> li(cond_equal->current_level);
    while ((item= li++))
    {
      if (item->contains(field))
        return item;
    }
    /* 
      The field is not found in any of the multiple equalities
      of the current level. Look for it in upper levels
    */
    cond_equal= cond_equal->upper_levels;
  }
  return 0;
}


3793 3794 3795 3796 3797 3798 3799 3800 3801 3802 3803 3804 3805 3806 3807 3808 3809 3810 3811 3812 3813 3814 3815 3816 3817 3818 3819 3820 3821 3822 3823 3824 3825 3826 3827
/*
  Check whether a field can be substituted by an equal item

  SYNOPSIS
    equal_fields_propagator()
      arg - *arg != NULL <-> the field is in the context where
            substitution for an equal item is valid
   
  DESCRIPTION
    The function checks whether a substitution of the field
    occurrence for an equal item is valid.

  NOTES
    The following statement is not always true:
    x=y => F(x)=F(x/y).
    This means substitution of an item for an equal item not always
    yields an equavalent condition.
    Here's an example:
      'a'='a '
      (LENGTH('a')=1) != (LENGTH('a ')=2)
    Such a substitution is surely valid if either the substituted
    field is not of a STRING type or if it is an argument of
    a comparison  predicate.  

  RETURN
    TRUE   substitution is valid
    FALSE  otherwise
*/

bool Item_field::subst_argument_checker(byte **arg)
{
  return (result_type() != STRING_RESULT) || (*arg);
}


3828
/*
3829 3830
  Set a pointer to the multiple equality the field reference belongs to
  (if any)
3831 3832 3833
   
  SYNOPSIS
    equal_fields_propagator()
3834 3835
      arg - reference to list of multiple equalities where
            the field (this object) is to be looked for
3836 3837 3838 3839 3840 3841 3842 3843 3844 3845 3846
  
  DESCRIPTION
    The function looks for a multiple equality containing the field item
    among those referenced by arg.
    In the case such equality exists the function does the following.
    If the found multiple equality contains a constant, then the field
    reference is substituted for this constant, otherwise it sets a pointer
    to the multiple equality in the field item.

  NOTES
    This function is supposed to be called as a callback parameter in calls
3847
    of the compile method.  
3848 3849 3850 3851 3852

  RETURN VALUES
    pointer to the replacing constant item, if the field item was substituted 
    pointer to the field item, otherwise.
*/
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3853

3854 3855 3856 3857 3858 3859 3860 3861
Item *Item_field::equal_fields_propagator(byte *arg)
{
  if (no_const_subst)
    return this;
  item_equal= find_item_equal((COND_EQUAL *) arg);
  Item *item= 0;
  if (item_equal)
    item= item_equal->get_const();
3862 3863 3864 3865 3866 3867 3868 3869 3870 3871 3872
  /*
    Disable const propagation for items used in different comparison contexts.
    This must be done because, for example, Item_hex_string->val_int() is not
    the same as (Item_hex_string->val_str() in BINARY column)->val_int().
    We cannot simply disable the replacement in a particular context (
    e.g. <bin_col> = <int_col> AND <bin_col> = <hex_string>) since
    Items don't know the context they are in and there are functions like 
    IF (<hex_string>, 'yes', 'no').
    The same problem occurs when comparing a DATE/TIME field with a
    DATE/TIME represented as an int and as a string.
  */
3873 3874
  if (!item ||
      (cmp_context != (Item_result)-1 && item->cmp_context != cmp_context))
3875 3876 3877 3878 3879 3880
    item= this;
  return item;
}


/*
3881 3882 3883 3884
  Mark the item to not be part of substitution if it's not a binary item
  See comments in Arg_comparator::set_compare_func() for details
*/

3885
bool Item_field::set_no_const_sub(byte *arg)
3886 3887 3888
{
  if (field->charset() != &my_charset_bin)
    no_const_subst=1;
3889
  return FALSE;
3890 3891 3892 3893
}


/*
3894
  Replace an Item_field for an equal Item_field that evaluated earlier
3895
  (if any)
3896 3897
   
  SYNOPSIS
3898
    replace_equal_field_()
3899 3900 3901
    arg - a dummy parameter, is not used here
  
  DESCRIPTION
3902 3903 3904 3905 3906
    The function returns a pointer to an item that is taken from
    the very beginning of the item_equal list which the Item_field
    object refers to (belongs to).  
    If the Item_field object does not refer any Item_equal object
    'this' is returned 
3907 3908 3909

  NOTES
    This function is supposed to be called as a callback parameter in calls
3910
    of the thransformer method.  
3911 3912

  RETURN VALUES
3913 3914
    pointer to a replacement Item_field if there is a better equal item;
    this - otherwise.
3915 3916
*/

3917
Item *Item_field::replace_equal_field(byte *arg)
3918 3919 3920 3921
{
  if (item_equal)
  {
    Item_field *subst= item_equal->get_first();
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3922
    if (subst && !field->eq(subst->field))
3923
      return subst;
3924
  }
3925
  return this;
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3926
}
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3927

3928

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3929 3930
void Item::init_make_field(Send_field *tmp_field,
			   enum enum_field_types field_type)
3931
{
3932
  char *empty_name= (char*) "";
3933
  tmp_field->db_name=		empty_name;
3934 3935 3936 3937
  tmp_field->org_table_name=	empty_name;
  tmp_field->org_col_name=	empty_name;
  tmp_field->table_name=	empty_name;
  tmp_field->col_name=		name;
3938
  tmp_field->charsetnr=         collation.collation->number;
3939 3940 3941
  tmp_field->flags=             (maybe_null ? 0 : NOT_NULL_FLAG) | 
                                (my_binary_compare(collation.collation) ?
                                 BINARY_FLAG : 0);
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3942 3943 3944
  tmp_field->type=field_type;
  tmp_field->length=max_length;
  tmp_field->decimals=decimals;
3945 3946
  if (unsigned_flag)
    tmp_field->flags |= UNSIGNED_FLAG;
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3947 3948
}

3949
void Item::make_field(Send_field *tmp_field)
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3950
{
3951
  init_make_field(tmp_field, field_type());
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3952 3953 3954
}


3955 3956
void Item_empty_string::make_field(Send_field *tmp_field)
{
3957 3958 3959 3960 3961
  enum_field_types type= FIELD_TYPE_VAR_STRING;
  if (max_length >= 16777216)
    type= FIELD_TYPE_LONG_BLOB;
  else if (max_length >= 65536)
    type= FIELD_TYPE_MEDIUM_BLOB;
3962
  init_make_field(tmp_field, type);
3963 3964
}

3965

3966
enum_field_types Item::field_type() const
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3967
{
3968
  switch (result_type()) {
3969 3970 3971 3972 3973 3974 3975
  case STRING_RESULT:  return MYSQL_TYPE_VARCHAR;
  case INT_RESULT:     return FIELD_TYPE_LONGLONG;
  case DECIMAL_RESULT: return FIELD_TYPE_NEWDECIMAL;
  case REAL_RESULT:    return FIELD_TYPE_DOUBLE;
  case ROW_RESULT:
  default:
    DBUG_ASSERT(0);
3976 3977
    return MYSQL_TYPE_VARCHAR;
  }
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3978 3979
}

3980

3981 3982 3983 3984 3985 3986 3987 3988 3989 3990 3991 3992 3993 3994 3995 3996
/*
  Create a field to hold a string value from an item

  SYNOPSIS
    make_string_field()
    table		Table for which the field is created

  IMPLEMENTATION
    If max_length > CONVERT_IF_BIGGER_TO_BLOB create a blob
    If max_length > 0 create a varchar
    If max_length == 0 create a CHAR(0) 
*/


Field *Item::make_string_field(TABLE *table)
{
3997 3998
  DBUG_ASSERT(collation.collation);
  if (max_length/collation.collation->mbmaxlen > CONVERT_IF_BIGGER_TO_BLOB)
3999 4000
    return new Field_blob(max_length, maybe_null, name, table,
                          collation.collation);
4001 4002 4003
  /* Item_type_holder holds the exact type, do not change it */
  if (max_length > 0 &&
      (type() != Item::TYPE_HOLDER || field_type() != MYSQL_TYPE_STRING))
4004 4005 4006 4007 4008 4009 4010
    return new Field_varstring(max_length, maybe_null, name, table,
                               collation.collation);
  return new Field_string(max_length, maybe_null, name, table,
                          collation.collation);
}


4011 4012 4013 4014 4015 4016 4017 4018 4019 4020 4021
/*
  Create a field based on field_type of argument

  For now, this is only used to create a field for
  IFNULL(x,something)

  RETURN
    0  error
    #  Created field
*/

4022 4023
Field *Item::tmp_table_field_from_field_type(TABLE *table)
{
4024 4025 4026 4027 4028 4029
  /*
    The field functions defines a field to be not null if null_ptr is not 0
  */
  uchar *null_ptr= maybe_null ? (uchar*) "" : 0;

  switch (field_type()) {
4030
  case MYSQL_TYPE_DECIMAL:
4031
  case MYSQL_TYPE_NEWDECIMAL:
4032
    return new Field_new_decimal((char*) 0, max_length, null_ptr, 0,
4033 4034
                                 Field::NONE, name, table, decimals, 0,
                                 unsigned_flag);
4035
  case MYSQL_TYPE_TINY:
4036 4037
    return new Field_tiny((char*) 0, max_length, null_ptr, 0, Field::NONE,
			  name, table, 0, unsigned_flag);
4038
  case MYSQL_TYPE_SHORT:
4039 4040
    return new Field_short((char*) 0, max_length, null_ptr, 0, Field::NONE,
			   name, table, 0, unsigned_flag);
4041
  case MYSQL_TYPE_LONG:
4042 4043
    return new Field_long((char*) 0, max_length, null_ptr, 0, Field::NONE,
			  name, table, 0, unsigned_flag);
4044 4045
#ifdef HAVE_LONG_LONG
  case MYSQL_TYPE_LONGLONG:
4046 4047
    return new Field_longlong((char*) 0, max_length, null_ptr, 0, Field::NONE,
			      name, table, 0, unsigned_flag);
4048
#endif
4049 4050 4051 4052 4053 4054 4055 4056 4057
  case MYSQL_TYPE_FLOAT:
    return new Field_float((char*) 0, max_length, null_ptr, 0, Field::NONE,
			   name, table, decimals, 0, unsigned_flag);
  case MYSQL_TYPE_DOUBLE:
    return new Field_double((char*) 0, max_length, null_ptr, 0, Field::NONE,
			    name, table, decimals, 0, unsigned_flag);
  case MYSQL_TYPE_NULL:
    return new Field_null((char*) 0, max_length, Field::NONE,
			  name, table, &my_charset_bin);
4058
  case MYSQL_TYPE_INT24:
4059 4060
    return new Field_medium((char*) 0, max_length, null_ptr, 0, Field::NONE,
			    name, table, 0, unsigned_flag);
4061
  case MYSQL_TYPE_NEWDATE:
4062 4063 4064 4065 4066
  case MYSQL_TYPE_DATE:
    return new Field_date(maybe_null, name, table, &my_charset_bin);
  case MYSQL_TYPE_TIME:
    return new Field_time(maybe_null, name, table, &my_charset_bin);
  case MYSQL_TYPE_TIMESTAMP:
4067
    return new Field_timestamp(maybe_null, name, table, &my_charset_bin);
4068 4069 4070
  case MYSQL_TYPE_DATETIME:
    return new Field_datetime(maybe_null, name, table, &my_charset_bin);
  case MYSQL_TYPE_YEAR:
4071 4072
    return new Field_year((char*) 0, max_length, null_ptr, 0, Field::NONE,
			  name, table);
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4073
  case MYSQL_TYPE_BIT:
4074
    return new Field_bit_as_char(NULL, max_length, null_ptr, 0,
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4075
                                 Field::NONE, name, table);
4076
  default:
4077
    /* This case should never be chosen */
4078 4079
    DBUG_ASSERT(0);
    /* If something goes awfully wrong, it's better to get a string than die */
4080 4081
  case MYSQL_TYPE_ENUM:
  case MYSQL_TYPE_SET:
4082
  case MYSQL_TYPE_STRING:
4083
  case MYSQL_TYPE_VAR_STRING:
4084
  case MYSQL_TYPE_VARCHAR:
4085
    return make_string_field(table);
4086 4087 4088 4089 4090
  case MYSQL_TYPE_TINY_BLOB:
  case MYSQL_TYPE_MEDIUM_BLOB:
  case MYSQL_TYPE_LONG_BLOB:
  case MYSQL_TYPE_BLOB:
  case MYSQL_TYPE_GEOMETRY:
4091 4092 4093 4094 4095
    if (this->type() == Item::TYPE_HOLDER)
      return new Field_blob(max_length, maybe_null, name, table,
                          collation.collation, 1);
    else
      return new Field_blob(max_length, maybe_null, name, table,
4096
                          collation.collation);
4097
    break;					// Blob handled outside of case
4098 4099 4100
  }
}

4101

4102 4103
/* ARGSUSED */
void Item_field::make_field(Send_field *tmp_field)
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4104
{
4105
  field->make_field(tmp_field);
4106
  DBUG_ASSERT(tmp_field->table_name != 0);
4107 4108
  if (name)
    tmp_field->col_name=name;			// Use user supplied name
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4109 4110
}

4111

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4112
/*
4113
  Set a field:s value from a item
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4114 4115 4116 4117 4118 4119 4120
*/

void Item_field::save_org_in_field(Field *to)
{
  if (field->is_null())
  {
    null_value=1;
4121
    set_field_to_null_with_conversions(to, 1);
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4122 4123 4124 4125 4126 4127 4128 4129 4130
  }
  else
  {
    to->set_notnull();
    field_conv(to,field);
    null_value=0;
  }
}

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4131
int Item_field::save_in_field(Field *to, bool no_conversions)
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4132 4133 4134 4135
{
  if (result_field->is_null())
  {
    null_value=1;
4136
    return set_field_to_null_with_conversions(to, no_conversions);
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4137 4138 4139 4140 4141 4142 4143 4144 4145 4146
  }
  else
  {
    to->set_notnull();
    field_conv(to,result_field);
    null_value=0;
  }
  return 0;
}

4147

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4148 4149 4150 4151 4152 4153 4154 4155 4156 4157 4158 4159 4160 4161 4162 4163
/*
  Store null in field

  SYNOPSIS
    save_in_field()
    field		Field where we want to store NULL

  DESCRIPTION
    This is used on INSERT.
    Allow NULL to be inserted in timestamp and auto_increment values

  RETURN VALUES
    0	 ok
    1	 Field doesn't support NULL values and can't handle 'field = NULL'
*/   

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4164
int Item_null::save_in_field(Field *field, bool no_conversions)
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4165
{
4166
  return set_field_to_null_with_conversions(field, no_conversions);
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4167 4168 4169
}


4170 4171 4172 4173 4174 4175 4176 4177
/*
  Store null in field

  SYNOPSIS
    save_safe_in_field()
    field		Field where we want to store NULL

  RETURN VALUES
4178
    0	 OK
4179 4180 4181
    1	 Field doesn't support NULL values
*/   

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4182
int Item_null::save_safe_in_field(Field *field)
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4183 4184 4185 4186 4187
{
  return set_field_to_null(field);
}


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4188
int Item::save_in_field(Field *field, bool no_conversions)
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4189
{
4190
  int error;
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4191 4192 4193 4194 4195
  if (result_type() == STRING_RESULT ||
      result_type() == REAL_RESULT &&
      field->result_type() == STRING_RESULT)
  {
    String *result;
4196
    CHARSET_INFO *cs= collation.collation;
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4197
    char buff[MAX_FIELD_WIDTH];		// Alloc buffer for small columns
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4198
    str_value.set_quick(buff, sizeof(buff), cs);
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4199 4200
    result=val_str(&str_value);
    if (null_value)
4201
    {
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4202
      str_value.set_quick(0, 0, cs);
4203
      return set_field_to_null_with_conversions(field, no_conversions);
4204
    }
4205 4206 4207

    /* NOTE: If null_value == FALSE, "result" must be not NULL.  */

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4208
    field->set_notnull();
4209
    error=field->store(result->ptr(),result->length(),cs);
4210
    str_value.set_quick(0, 0, cs);
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4211 4212 4213
  }
  else if (result_type() == REAL_RESULT)
  {
4214
    double nr= val_real();
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4215 4216 4217
    if (null_value)
      return set_field_to_null(field);
    field->set_notnull();
4218
    error=field->store(nr);
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4219
  }
4220 4221 4222 4223 4224 4225 4226 4227 4228
  else if (result_type() == DECIMAL_RESULT)
  {
    my_decimal decimal_value;
    my_decimal *value= val_decimal(&decimal_value);
    if (null_value)
      return set_field_to_null(field);
    field->set_notnull();
    error=field->store_decimal(value);
  }
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4229 4230 4231 4232
  else
  {
    longlong nr=val_int();
    if (null_value)
4233
      return set_field_to_null_with_conversions(field, no_conversions);
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4234
    field->set_notnull();
4235
    error=field->store(nr, unsigned_flag);
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4236
  }
4237
  return error;
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4238 4239
}

4240

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4241
int Item_string::save_in_field(Field *field, bool no_conversions)
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4242 4243 4244 4245 4246 4247
{
  String *result;
  result=val_str(&str_value);
  if (null_value)
    return set_field_to_null(field);
  field->set_notnull();
4248
  return field->store(result->ptr(),result->length(),collation.collation);
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4249 4250
}

4251

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4252
int Item_uint::save_in_field(Field *field, bool no_conversions)
4253
{
4254
  /* Item_int::save_in_field handles both signed and unsigned. */
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4255
  return Item_int::save_in_field(field, no_conversions);
4256 4257
}

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4258 4259

int Item_int::save_in_field(Field *field, bool no_conversions)
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4260 4261 4262 4263 4264
{
  longlong nr=val_int();
  if (null_value)
    return set_field_to_null(field);
  field->set_notnull();
4265
  return field->store(nr, unsigned_flag);
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4266 4267
}

4268 4269 4270 4271 4272 4273 4274 4275

int Item_decimal::save_in_field(Field *field, bool no_conversions)
{
  field->set_notnull();
  return field->store_decimal(&decimal_value);
}


4276 4277 4278 4279 4280 4281 4282 4283 4284 4285 4286 4287 4288 4289 4290 4291
bool Item_int::eq(const Item *arg, bool binary_cmp) const
{
  /* No need to check for null value as basic constant can't be NULL */
  if (arg->basic_const_item() && arg->type() == type())
  {
    /*
      We need to cast off const to call val_int(). This should be OK for
      a basic constant.
    */
    Item *item= (Item*) arg;
    return item->val_int() == value && item->unsigned_flag == unsigned_flag;
  }
  return FALSE;
}


4292 4293
Item *Item_int_with_ref::new_item()
{
4294
  DBUG_ASSERT(ref->const_item());
4295 4296 4297 4298 4299 4300 4301 4302 4303 4304
  /*
    We need to evaluate the constant to make sure it works with
    parameter markers.
  */
  return (ref->unsigned_flag ?
          new Item_uint(ref->name, ref->val_int(), ref->max_length) :
          new Item_int(ref->name, ref->val_int(), ref->max_length));
}


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4305 4306
Item_num *Item_uint::neg()
{
4307
  Item_decimal *item= new Item_decimal(value, 1);
4308
  return item->neg();
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4309
}
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4310

4311

4312 4313 4314 4315 4316 4317 4318 4319 4320 4321 4322 4323 4324 4325 4326 4327 4328 4329 4330 4331 4332 4333 4334
static uint nr_of_decimals(const char *str, const char *end)
{
  const char *decimal_point;

  /* Find position for '.' */
  for (;;)
  {
    if (str == end)
      return 0;
    if (*str == 'e' || *str == 'E')
      return NOT_FIXED_DEC;    
    if (*str++ == '.')
      break;
  }
  decimal_point= str;
  for (; my_isdigit(system_charset_info, *str) ; str++)
    ;
  if (*str == 'e' || *str == 'E')
    return NOT_FIXED_DEC;
  return (uint) (str - decimal_point);
}


4335 4336 4337 4338 4339
/*
  This function is only called during parsing. We will signal an error if
  value is not a true double value (overflow)
*/

4340
Item_float::Item_float(const char *str_arg, uint length)
4341 4342
{
  int error;
4343 4344 4345
  char *end_not_used;
  value= my_strntod(&my_charset_bin, (char*) str_arg, length, &end_not_used,
                    &error);
4346 4347 4348 4349 4350 4351 4352
  if (error)
  {
    /*
      Note that we depend on that str_arg is null terminated, which is true
      when we are in the parser
    */
    DBUG_ASSERT(str_arg[length] == 0);
4353
    my_error(ER_ILLEGAL_VALUE_FOR_TYPE, MYF(0), "double", (char*) str_arg);
4354 4355
  }
  presentation= name=(char*) str_arg;
4356
  decimals=(uint8) nr_of_decimals(str_arg, str_arg+length);
4357 4358 4359 4360 4361
  max_length=length;
  fixed= 1;
}


4362
int Item_float::save_in_field(Field *field, bool no_conversions)
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4363
{
4364
  double nr= val_real();
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4365 4366 4367
  if (null_value)
    return set_field_to_null(field);
  field->set_notnull();
4368
  return field->store(nr);
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4369 4370
}

4371

4372
void Item_float::print(String *str)
4373 4374 4375 4376 4377 4378 4379 4380 4381 4382 4383 4384 4385
{
  if (presentation)
  {
    str->append(presentation);
    return;
  }
  char buffer[20];
  String num(buffer, sizeof(buffer), &my_charset_bin);
  num.set(value, decimals, &my_charset_bin);
  str->append(num);
}


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4386 4387 4388 4389 4390
/*
  hex item
  In string context this is a binary string.
  In number context this is a longlong value.
*/
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4391

4392
bool Item_float::eq(const Item *arg, bool binary_cmp) const
4393 4394 4395 4396 4397 4398 4399 4400
{
  if (arg->basic_const_item() && arg->type() == type())
  {
    /*
      We need to cast off const to call val_int(). This should be OK for
      a basic constant.
    */
    Item *item= (Item*) arg;
4401
    return item->val_real() == value;
4402 4403 4404 4405
  }
  return FALSE;
}

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4406

4407
inline uint char_val(char X)
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4408 4409 4410 4411 4412 4413
{
  return (uint) (X >= '0' && X <= '9' ? X-'0' :
		 X >= 'A' && X <= 'Z' ? X-'A'+10 :
		 X-'a'+10);
}

4414

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4415
Item_hex_string::Item_hex_string(const char *str, uint str_length)
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4416 4417 4418 4419 4420 4421
{
  name=(char*) str-2;				// Lex makes this start with 0x
  max_length=(str_length+1)/2;
  char *ptr=(char*) sql_alloc(max_length+1);
  if (!ptr)
    return;
4422
  str_value.set(ptr,max_length,&my_charset_bin);
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4423 4424 4425 4426 4427 4428 4429 4430 4431
  char *end=ptr+max_length;
  if (max_length*2 != str_length)
    *ptr++=char_val(*str++);			// Not even, assume 0 prefix
  while (ptr != end)
  {
    *ptr++= (char) (char_val(str[0])*16+char_val(str[1]));
    str+=2;
  }
  *ptr=0;					// Keep purify happy
4432
  collation.set(&my_charset_bin, DERIVATION_COERCIBLE);
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4433
  fixed= 1;
4434
  unsigned_flag= 1;
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4435 4436
}

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4437
longlong Item_hex_string::val_int()
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4438
{
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4439
  // following assert is redundant, because fixed=1 assigned in constructor
4440
  DBUG_ASSERT(fixed == 1);
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4441 4442 4443 4444 4445 4446 4447 4448 4449 4450
  char *end=(char*) str_value.ptr()+str_value.length(),
       *ptr=end-min(str_value.length(),sizeof(longlong));

  ulonglong value=0;
  for (; ptr != end ; ptr++)
    value=(value << 8)+ (ulonglong) (uchar) *ptr;
  return (longlong) value;
}


4451 4452 4453 4454 4455 4456 4457 4458 4459 4460
my_decimal *Item_hex_string::val_decimal(my_decimal *decimal_value)
{
  // following assert is redundant, because fixed=1 assigned in constructor
  DBUG_ASSERT(fixed == 1);
  ulonglong value= (ulonglong)val_int();
  int2my_decimal(E_DEC_FATAL_ERROR, value, TRUE, decimal_value);
  return (decimal_value);
}


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4461
int Item_hex_string::save_in_field(Field *field, bool no_conversions)
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4462
{
4463
  int error;
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4464 4465 4466
  field->set_notnull();
  if (field->result_type() == STRING_RESULT)
  {
4467
    error=field->store(str_value.ptr(),str_value.length(),collation.collation);
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4468 4469 4470 4471
  }
  else
  {
    longlong nr=val_int();
4472
    error=field->store(nr, TRUE);    // Assume hex numbers are unsigned
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4473
  }
4474
  return error;
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4475 4476 4477
}


4478
bool Item_hex_string::eq(const Item *arg, bool binary_cmp) const
4479 4480 4481 4482 4483 4484 4485 4486 4487 4488
{
  if (arg->basic_const_item() && arg->type() == type())
  {
    if (binary_cmp)
      return !stringcmp(&str_value, &arg->str_value);
    return !sortcmp(&str_value, &arg->str_value, collation.collation);
  }
  return FALSE;
}

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4489

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4490
Item *Item_hex_string::safe_charset_converter(CHARSET_INFO *tocs)
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4491 4492 4493 4494 4495 4496 4497
{
  Item_string *conv;
  String tmp, *str= val_str(&tmp);

  if (!(conv= new Item_string(str->ptr(), str->length(), tocs)))
    return NULL;
  conv->str_value.copy();
4498
  conv->str_value.mark_as_const();
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4499 4500 4501 4502
  return conv;
}


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/*
  bin item.
  In string context this is a binary string.
  In number context this is a longlong value.
*/
  
Item_bin_string::Item_bin_string(const char *str, uint str_length)
{
  const char *end= str + str_length - 1;
  uchar bits= 0;
  uint power= 1;

  name= (char*) str - 2;
  max_length= (str_length + 7) >> 3;
  char *ptr= (char*) sql_alloc(max_length + 1);
  if (!ptr)
    return;
  str_value.set(ptr, max_length, &my_charset_bin);
  ptr+= max_length - 1;
  ptr[1]= 0;                     // Set end null for string
  for (; end >= str; end--)
  {
    if (power == 256)
    {
      power= 1;
      *ptr--= bits;
      bits= 0;     
    }
    if (*end == '1')
      bits|= power; 
    power<<= 1;
  }
  *ptr= (char) bits;
  collation.set(&my_charset_bin, DERIVATION_COERCIBLE);
  fixed= 1;
}


4541 4542 4543 4544 4545
/*
  Pack data in buffer for sending
*/

bool Item_null::send(Protocol *protocol, String *packet)
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4546
{
4547
  return protocol->store_null();
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4548 4549 4550
}

/*
4551
  This is only called from items that is not of type item_field
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4552 4553
*/

4554
bool Item::send(Protocol *protocol, String *buffer)
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4555
{
4556 4557
  bool result;
  enum_field_types type;
4558
  LINT_INIT(result);                     // Will be set if null_value == 0
4559 4560 4561

  switch ((type=field_type())) {
  default:
4562 4563 4564 4565 4566 4567 4568 4569 4570
  case MYSQL_TYPE_NULL:
  case MYSQL_TYPE_DECIMAL:
  case MYSQL_TYPE_ENUM:
  case MYSQL_TYPE_SET:
  case MYSQL_TYPE_TINY_BLOB:
  case MYSQL_TYPE_MEDIUM_BLOB:
  case MYSQL_TYPE_LONG_BLOB:
  case MYSQL_TYPE_BLOB:
  case MYSQL_TYPE_GEOMETRY:
4571 4572
  case MYSQL_TYPE_STRING:
  case MYSQL_TYPE_VAR_STRING:
4573
  case MYSQL_TYPE_VARCHAR:
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4574
  case MYSQL_TYPE_BIT:
4575
  case MYSQL_TYPE_NEWDECIMAL:
4576 4577 4578
  {
    String *res;
    if ((res=val_str(buffer)))
4579
      result= protocol->store(res->ptr(),res->length(),res->charset());
4580 4581 4582 4583 4584 4585 4586 4587 4588 4589 4590
    break;
  }
  case MYSQL_TYPE_TINY:
  {
    longlong nr;
    nr= val_int();
    if (!null_value)
      result= protocol->store_tiny(nr);
    break;
  }
  case MYSQL_TYPE_SHORT:
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4591
  case MYSQL_TYPE_YEAR:
4592 4593 4594 4595 4596 4597 4598
  {
    longlong nr;
    nr= val_int();
    if (!null_value)
      result= protocol->store_short(nr);
    break;
  }
4599
  case MYSQL_TYPE_INT24:
4600 4601 4602 4603 4604 4605 4606 4607 4608 4609 4610 4611 4612 4613 4614 4615
  case MYSQL_TYPE_LONG:
  {
    longlong nr;
    nr= val_int();
    if (!null_value)
      result= protocol->store_long(nr);
    break;
  }
  case MYSQL_TYPE_LONGLONG:
  {
    longlong nr;
    nr= val_int();
    if (!null_value)
      result= protocol->store_longlong(nr, unsigned_flag);
    break;
  }
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4616 4617 4618
  case MYSQL_TYPE_FLOAT:
  {
    float nr;
4619
    nr= (float) val_real();
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4620 4621 4622 4623
    if (!null_value)
      result= protocol->store(nr, decimals, buffer);
    break;
  }
4624 4625
  case MYSQL_TYPE_DOUBLE:
  {
4626
    double nr= val_real();
4627 4628 4629 4630 4631 4632
    if (!null_value)
      result= protocol->store(nr, decimals, buffer);
    break;
  }
  case MYSQL_TYPE_DATETIME:
  case MYSQL_TYPE_DATE:
4633
  case MYSQL_TYPE_TIMESTAMP:
4634 4635
  {
    TIME tm;
4636
    get_date(&tm, TIME_FUZZY_DATE);
4637 4638 4639 4640 4641 4642 4643 4644 4645 4646 4647 4648 4649 4650 4651 4652 4653 4654 4655 4656 4657
    if (!null_value)
    {
      if (type == MYSQL_TYPE_DATE)
	return protocol->store_date(&tm);
      else
	result= protocol->store(&tm);
    }
    break;
  }
  case MYSQL_TYPE_TIME:
  {
    TIME tm;
    get_time(&tm);
    if (!null_value)
      result= protocol->store_time(&tm);
    break;
  }
  }
  if (null_value)
    result= protocol->store_null();
  return result;
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4658 4659
}

4660 4661

bool Item_field::send(Protocol *protocol, String *buffer)
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4662
{
4663
  return protocol->store(result_field);
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4664 4665
}

4666

4667 4668 4669 4670 4671
Item_ref::Item_ref(Name_resolution_context *context_arg,
                   Item **item, const char *table_name_arg,
                   const char *field_name_arg)
  :Item_ident(context_arg, NullS, table_name_arg, field_name_arg),
   result_field(0), ref(item)
4672 4673 4674 4675
{
  /*
    This constructor used to create some internals references over fixed items
  */
4676
  DBUG_ASSERT(ref != 0);
4677
  if (*ref && (*ref)->fixed)
4678 4679 4680 4681
    set_properties();
}


4682
/*
4683
  Resolve the name of a reference to a column reference.
4684 4685 4686

  SYNOPSIS
    Item_ref::fix_fields()
4687 4688
    thd       [in]      current thread
    reference [in/out]  view column if this item was resolved to a view column
4689 4690

  DESCRIPTION
4691 4692
    The method resolves the column reference represented by 'this' as a column
    present in one of: GROUP BY clause, SELECT clause, outer queries. It is
4693 4694
    used typically for columns in the HAVING clause which are not under
    aggregate functions.
4695 4696

  NOTES
4697 4698
    The name resolution algorithm used is (where [T_j] is an optional table
    name that qualifies the column name):
4699

4700 4701 4702
      resolve_extended([T_j].col_ref_i)
      {
        Search for a column or derived column named col_ref_i [in table T_j]
4703
        in the SELECT and GROUP clauses of Q.
4704

4705 4706
        if such a column is NOT found AND    // Lookup in outer queries.
           there are outer queries
4707 4708 4709
        {
          for each outer query Q_k beginning from the inner-most one
         {
4710 4711 4712 4713 4714 4715 4716 4717
            Search for a column or derived column named col_ref_i
            [in table T_j] in the SELECT and GROUP clauses of Q_k.

            if such a column is not found AND
               - Q_k is not a group query AND
               - Q_k is not inside an aggregate function
               OR
               - Q_(k-1) is not in a HAVING or SELECT clause of Q_k
4718 4719 4720 4721 4722 4723 4724
            {
              search for a column or derived column named col_ref_i
              [in table T_j] in the FROM clause of Q_k;
            }
          }
        }
      }
4725 4726

    This procedure treats GROUP BY and SELECT clauses as one namespace for
4727 4728 4729
    column references in HAVING. Notice that compared to
    Item_field::fix_fields, here we first search the SELECT and GROUP BY
    clauses, and then we search the FROM clause.
4730

4731 4732 4733
  POSTCONDITION
    Item_ref::ref is 0 or points to a valid item

4734 4735 4736 4737
  RETURN
    TRUE  if error
    FALSE on success
*/
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4738

4739
bool Item_ref::fix_fields(THD *thd, Item **reference)
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4740
{
4741
  enum_parsing_place place= NO_MATTER;
4742
  DBUG_ASSERT(fixed == 0);
4743 4744
  SELECT_LEX *current_sel= thd->lex->current_select;

4745
  if (!ref || ref == not_found_item)
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4746
  {
4747 4748 4749
    if (!(ref= resolve_ref_in_select_and_group(thd, this,
                                               context->select_lex)))
      goto error;             /* Some error occurred (e.g. ambiguous names). */
4750

4751
    if (ref == not_found_item) /* This reference was not resolved. */
4752
    {
4753 4754
      Name_resolution_context *last_checked_context= context;
      Name_resolution_context *outer_context= context->outer_context;
4755 4756 4757
      Field *from_field;
      ref= 0;

4758
      if (!outer_context)
4759 4760 4761 4762
      {
        /* The current reference cannot be resolved in this query. */
        my_error(ER_BAD_FIELD_ERROR,MYF(0),
                 this->full_name(), current_thd->where);
4763
        goto error;
4764
      }
4765

4766
      /*
4767 4768 4769
        If there is an outer context (select), and it is not a derived table
        (which do not support the use of outer fields for now), try to
        resolve this reference in the outer select(s).
4770

4771 4772 4773
        We treat each subselect as a separate namespace, so that different
        subselects may contain columns with the same names. The subselects are
        searched starting from the innermost.
4774
      */
4775 4776
      from_field= (Field*) not_found_field;

4777
      do
4778
      {
4779 4780 4781 4782
        SELECT_LEX *select= outer_context->select_lex;
        Item_subselect *prev_subselect_item=
          last_checked_context->select_lex->master_unit()->item;
        last_checked_context= outer_context;
4783

4784
        /* Search in the SELECT and GROUP lists of the outer select. */
4785
        if (outer_context->resolve_in_select_list)
4786
        {
4787 4788
          if (!(ref= resolve_ref_in_select_and_group(thd, this, select)))
            goto error; /* Some error occurred (e.g. ambiguous names). */
4789
          if (ref != not_found_item)
4790
          {
4791 4792 4793 4794
            DBUG_ASSERT(*ref && (*ref)->fixed);
            prev_subselect_item->used_tables_cache|= (*ref)->used_tables();
            prev_subselect_item->const_item_cache&= (*ref)->const_item();
            break;
4795 4796
          }
          /*
4797 4798 4799
            Set ref to 0 to ensure that we get an error in case we replaced
            this item with another item and still use this item in some
            other place of the parse tree.
4800
          */
4801
          ref= 0;
4802
        }
4803

4804 4805 4806 4807 4808
        place= prev_subselect_item->parsing_place;
        /*
          Check table fields only if the subquery is used somewhere out of
          HAVING or the outer SELECT does not use grouping (i.e. tables are
          accessible).
4809
          TODO:
4810 4811 4812 4813 4814 4815
          Here we could first find the field anyway, and then test this
          condition, so that we can give a better error message -
          ER_WRONG_FIELD_WITH_GROUP, instead of the less informative
          ER_BAD_FIELD_ERROR which we produce now.
        */
        if ((place != IN_HAVING ||
4816 4817
             (!select->with_sum_func &&
              select->group_list.elements == 0)))
4818
        {
4819
          /*
4820 4821 4822
            In case of view, find_field_in_tables() write pointer to view
            field expression to 'reference', i.e. it substitute that
            expression instead of this Item_ref
4823
          */
4824
          from_field= find_field_in_tables(thd, this,
4825 4826 4827 4828
                                           outer_context->
                                             first_name_resolution_table,
                                           outer_context->
                                             last_name_resolution_table,
4829 4830
                                           reference,
                                           IGNORE_EXCEPT_NON_UNIQUE,
4831
                                           TRUE, TRUE);
4832
          if (! from_field)
4833
            goto error;
4834
          if (from_field == view_ref_found)
4835
          {
4836 4837 4838 4839 4840 4841
            Item::Type type= (*reference)->type();
            prev_subselect_item->used_tables_cache|=
              (*reference)->used_tables();
            prev_subselect_item->const_item_cache&=
              (*reference)->const_item();
            DBUG_ASSERT((*reference)->type() == REF_ITEM);
4842 4843
            mark_as_dependent(thd, last_checked_context->select_lex,
                              context->select_lex, this,
4844 4845 4846 4847 4848 4849 4850
                              ((type == REF_ITEM || type == FIELD_ITEM) ?
                               (Item_ident*) (*reference) :
                               0));
            /*
              view reference found, we substituted it instead of this
              Item, so can quit
            */
4851 4852
            return FALSE;
          }
4853 4854
          if (from_field != not_found_field)
          {
4855 4856 4857 4858 4859 4860 4861 4862 4863 4864 4865 4866 4867 4868 4869 4870 4871 4872 4873
            if (cached_table && cached_table->select_lex &&
                outer_context->select_lex &&
                cached_table->select_lex != outer_context->select_lex)
            {
              /*
                Due to cache, find_field_in_tables() can return field which
                doesn't belong to provided outer_context. In this case we have
                to find proper field context in order to fix field correcly.
              */
              do
              {
                outer_context= outer_context->outer_context;
                select= outer_context->select_lex;
                prev_subselect_item=
                  last_checked_context->select_lex->master_unit()->item;
                last_checked_context= outer_context;
              } while (outer_context && outer_context->select_lex &&
                       cached_table->select_lex != outer_context->select_lex);
            }
4874 4875 4876 4877
            prev_subselect_item->used_tables_cache|= from_field->table->map;
            prev_subselect_item->const_item_cache= 0;
            break;
          }
4878
        }
4879 4880 4881 4882 4883 4884
        DBUG_ASSERT(from_field == not_found_field);

        /* Reference is not found => depend on outer (or just error). */
        prev_subselect_item->used_tables_cache|= OUTER_REF_TABLE_BIT;
        prev_subselect_item->const_item_cache= 0;

4885 4886
        outer_context= outer_context->outer_context;
      } while (outer_context);
4887 4888 4889

      DBUG_ASSERT(from_field != 0 && from_field != view_ref_found);
      if (from_field != not_found_field)
4890
      {
4891 4892
        Item_field* fld;
        if (!(fld= new Item_field(from_field)))
4893
          goto error;
4894
        thd->change_item_tree(reference, fld);
4895 4896
        mark_as_dependent(thd, last_checked_context->select_lex,
                          thd->lex->current_select, this, fld);
4897 4898 4899 4900 4901 4902
        return FALSE;
      }
      if (ref == 0)
      {
        /* The item was not a table field and not a reference */
        my_error(ER_BAD_FIELD_ERROR, MYF(0),
4903
                 this->full_name(), current_thd->where);
4904
        goto error;
4905
      }
4906 4907
      /* Should be checked in resolve_ref_in_select_and_group(). */
      DBUG_ASSERT(*ref && (*ref)->fixed);
4908 4909
      mark_as_dependent(thd, last_checked_context->select_lex,
                        context->select_lex, this, this);
4910
    }
bk@work.mysql.com's avatar
bk@work.mysql.com committed
4911
  }
4912

4913
  DBUG_ASSERT(*ref);
4914
  /*
4915 4916 4917
    Check if this is an incorrect reference in a group function or forward
    reference. Do not issue an error if this is an unnamed reference inside an
    aggregate function.
4918
  */
4919
  if (((*ref)->with_sum_func && name &&
igor@rurik.mysql.com's avatar
igor@rurik.mysql.com committed
4920 4921
       !(current_sel->linkage != GLOBAL_OPTIONS_TYPE &&
         current_sel->having_fix_field)) ||
4922 4923
      !(*ref)->fixed)
  {
4924 4925 4926 4927
    my_error(ER_ILLEGAL_REFERENCE, MYF(0),
             name, ((*ref)->with_sum_func?
                    "reference to group function":
                    "forward reference in item list"));
4928
    goto error;
4929
  }
4930 4931 4932

  set_properties();

4933
  if ((*ref)->check_cols(1))
4934
    goto error;
4935
  return FALSE;
4936 4937 4938 4939

error:
  context->process_error(thd);
  return TRUE;
4940 4941
}

4942

4943 4944
void Item_ref::set_properties()
{
4945 4946 4947
  max_length= (*ref)->max_length;
  maybe_null= (*ref)->maybe_null;
  decimals=   (*ref)->decimals;
4948
  collation.set((*ref)->collation);
monty@mysql.com's avatar
monty@mysql.com committed
4949 4950 4951 4952
  /*
    We have to remember if we refer to a sum function, to ensure that
    split_sum_func() doesn't try to change the reference.
  */
monty@mashka.mysql.fi's avatar
monty@mashka.mysql.fi committed
4953
  with_sum_func= (*ref)->with_sum_func;
timour@mysql.com's avatar
Merge  
timour@mysql.com committed
4954
  unsigned_flag= (*ref)->unsigned_flag;
4955 4956 4957 4958
  if ((*ref)->type() == FIELD_ITEM)
    alias_name_used= ((Item_ident *) (*ref))->alias_name_used;
  else
    alias_name_used= TRUE; // it is not field, so it is was resolved by alias
4959
  fixed= 1;
bk@work.mysql.com's avatar
bk@work.mysql.com committed
4960 4961
}

4962

hf@deer.(none)'s avatar
hf@deer.(none) committed
4963 4964
void Item_ref::cleanup()
{
4965
  DBUG_ENTER("Item_ref::cleanup");
hf@deer.(none)'s avatar
hf@deer.(none) committed
4966
  Item_ident::cleanup();
4967
  result_field= 0;
4968
  DBUG_VOID_RETURN;
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hf@deer.(none) committed
4969 4970 4971
}


4972 4973
void Item_ref::print(String *str)
{
4974
  if (ref)
igor@rurik.mysql.com's avatar
igor@rurik.mysql.com committed
4975 4976 4977 4978 4979 4980 4981 4982 4983 4984
  {
    if ((*ref)->type() != Item::CACHE_ITEM && ref_type() != VIEW_REF &&
        name && alias_name_used)
    {
      THD *thd= current_thd;
      append_identifier(thd, str, name, (uint) strlen(name));
    }
    else
      (*ref)->print(str);
  }
4985 4986 4987 4988 4989
  else
    Item_ident::print(str);
}


4990 4991 4992 4993 4994 4995 4996 4997
bool Item_ref::send(Protocol *prot, String *tmp)
{
  if (result_field)
    return prot->store(result_field);
  return (*ref)->send(prot, tmp);
}


4998 4999 5000 5001 5002 5003 5004 5005
double Item_ref::val_result()
{
  if (result_field)
  {
    if ((null_value= result_field->is_null()))
      return 0.0;
    return result_field->val_real();
  }
5006
  return val_real();
5007 5008 5009 5010 5011 5012 5013 5014
}


longlong Item_ref::val_int_result()
{
  if (result_field)
  {
    if ((null_value= result_field->is_null()))
5015
      return 0;
5016 5017 5018 5019 5020 5021 5022 5023 5024 5025 5026 5027 5028 5029 5030 5031 5032 5033 5034
    return result_field->val_int();
  }
  return val_int();
}


String *Item_ref::str_result(String* str)
{
  if (result_field)
  {
    if ((null_value= result_field->is_null()))
      return 0;
    str->set_charset(str_value.charset());
    return result_field->val_str(str, &str_value);
  }
  return val_str(str);
}


5035 5036 5037 5038 5039 5040 5041 5042 5043 5044 5045 5046 5047 5048 5049 5050 5051 5052
my_decimal *Item_ref::val_decimal_result(my_decimal *decimal_value)
{
  if (result_field)
  {
    if ((null_value= result_field->is_null()))
      return 0;
    return result_field->val_decimal(decimal_value);
  }
  return val_decimal(decimal_value);
}


bool Item_ref::val_bool_result()
{
  if (result_field)
  {
    if ((null_value= result_field->is_null()))
      return 0;
5053
    switch (result_field->result_type()) {
5054
    case INT_RESULT:
5055
      return result_field->val_int() != 0;
5056
    case DECIMAL_RESULT:
5057 5058 5059 5060 5061 5062 5063
    {
      my_decimal decimal_value;
      my_decimal *val= result_field->val_decimal(&decimal_value);
      if (val)
        return !my_decimal_is_zero(val);
      return 0;
    }
5064 5065 5066 5067 5068 5069 5070 5071 5072 5073 5074 5075 5076 5077 5078 5079 5080 5081 5082 5083 5084 5085 5086 5087 5088 5089 5090 5091 5092 5093 5094 5095 5096 5097 5098 5099 5100 5101 5102 5103 5104 5105 5106 5107 5108 5109 5110 5111 5112 5113 5114
    case REAL_RESULT:
    case STRING_RESULT:
      return result_field->val_real() != 0.0;
    case ROW_RESULT:
    default:
      DBUG_ASSERT(0);
    }
  }
  return val_bool();
}


double Item_ref::val_real()
{
  DBUG_ASSERT(fixed);
  double tmp=(*ref)->val_result();
  null_value=(*ref)->null_value;
  return tmp;
}


longlong Item_ref::val_int()
{
  DBUG_ASSERT(fixed);
  longlong tmp=(*ref)->val_int_result();
  null_value=(*ref)->null_value;
  return tmp;
}


bool Item_ref::val_bool()
{
  DBUG_ASSERT(fixed);
  bool tmp= (*ref)->val_bool_result();
  null_value= (*ref)->null_value;
  return tmp;
}


String *Item_ref::val_str(String* tmp)
{
  DBUG_ASSERT(fixed);
  tmp=(*ref)->str_result(tmp);
  null_value=(*ref)->null_value;
  return tmp;
}


bool Item_ref::is_null()
{
  DBUG_ASSERT(fixed);
5115
  return (*ref)->is_null();
5116 5117 5118 5119 5120 5121 5122 5123 5124 5125 5126
}


bool Item_ref::get_date(TIME *ltime,uint fuzzydate)
{
  return (null_value=(*ref)->get_date_result(ltime,fuzzydate));
}


my_decimal *Item_ref::val_decimal(my_decimal *decimal_value)
{
igor@rurik.mysql.com's avatar
igor@rurik.mysql.com committed
5127
  my_decimal *val= (*ref)->val_decimal_result(decimal_value);
5128 5129 5130 5131
  null_value= (*ref)->null_value;
  return val;
}

5132 5133 5134
int Item_ref::save_in_field(Field *to, bool no_conversions)
{
  int res;
5135 5136
  if (result_field)
  {
5137 5138 5139 5140 5141
    if (result_field->is_null())
    {
      null_value= 1;
      return set_field_to_null_with_conversions(to, no_conversions);
    }
5142 5143 5144
    to->set_notnull();
    field_conv(to, result_field);
    null_value= 0;
5145 5146 5147 5148 5149 5150 5151
    return 0;
  }
  res= (*ref)->save_in_field(to, no_conversions);
  null_value= (*ref)->null_value;
  return res;
}

5152

5153 5154 5155 5156 5157 5158
void Item_ref::save_org_in_field(Field *field)
{
  (*ref)->save_org_in_field(field);
}


5159 5160 5161 5162 5163 5164 5165 5166 5167 5168
void Item_ref::make_field(Send_field *field)
{
  (*ref)->make_field(field);
  /* Non-zero in case of a view */
  if (name)
    field->col_name= name;
  if (table_name)
    field->table_name= table_name;
  if (db_name)
    field->db_name= db_name;
5169
}
5170 5171


5172 5173
void Item_ref_null_helper::print(String *str)
{
5174
  str->append(STRING_WITH_LEN("<ref_null_helper>("));
5175
  if (ref)
5176 5177 5178 5179 5180 5181 5182
    (*ref)->print(str);
  else
    str->append('?');
  str->append(')');
}


5183 5184 5185 5186 5187 5188 5189 5190 5191 5192 5193 5194 5195 5196 5197 5198 5199 5200 5201 5202 5203 5204 5205 5206 5207 5208 5209 5210 5211 5212 5213 5214 5215 5216 5217 5218 5219 5220 5221 5222 5223 5224
double Item_direct_ref::val_real()
{
  double tmp=(*ref)->val_real();
  null_value=(*ref)->null_value;
  return tmp;
}


longlong Item_direct_ref::val_int()
{
  longlong tmp=(*ref)->val_int();
  null_value=(*ref)->null_value;
  return tmp;
}


String *Item_direct_ref::val_str(String* tmp)
{
  tmp=(*ref)->val_str(tmp);
  null_value=(*ref)->null_value;
  return tmp;
}


my_decimal *Item_direct_ref::val_decimal(my_decimal *decimal_value)
{
  my_decimal *tmp= (*ref)->val_decimal(decimal_value);
  null_value=(*ref)->null_value;
  return tmp;
}


bool Item_direct_ref::val_bool()
{
  bool tmp= (*ref)->val_bool();
  null_value=(*ref)->null_value;
  return tmp;
}


bool Item_direct_ref::is_null()
{
monty@mysql.com's avatar
monty@mysql.com committed
5225
  return (*ref)->is_null();
5226 5227 5228 5229 5230 5231 5232 5233 5234
}


bool Item_direct_ref::get_date(TIME *ltime,uint fuzzydate)
{
  return (null_value=(*ref)->get_date(ltime,fuzzydate));
}


5235 5236 5237 5238 5239 5240 5241 5242 5243 5244 5245 5246 5247 5248 5249 5250 5251 5252 5253 5254 5255 5256 5257 5258
/*
  Prepare referenced view viewld then call usual Item_direct_ref::fix_fields

  SYNOPSIS
    Item_direct_view_ref::fix_fields()
    thd         thread handler
    reference   reference on reference where this item stored

  RETURN
    FALSE   OK
    TRUE    Error
*/

bool Item_direct_view_ref::fix_fields(THD *thd, Item **reference)
{
  /* view fild reference must be defined */
  DBUG_ASSERT(*ref);
  /* (*ref)->check_cols() will be made in Item_direct_ref::fix_fields */
  if (!(*ref)->fixed &&
      ((*ref)->fix_fields(thd, ref)))
    return TRUE;
  return Item_direct_ref::fix_fields(thd, reference);
}

5259
/*
5260
  Compare two view column references for equality.
5261 5262 5263 5264 5265 5266 5267

  SYNOPSIS
    Item_direct_view_ref::eq()
    item        item to compare with
    binary_cmp  make binary comparison

  DESCRIPTION
5268 5269
    A view column reference is considered equal to another column
    reference if the second one is a view column and if both column
igor@rurik.mysql.com's avatar
igor@rurik.mysql.com committed
5270 5271
    references resolve to the same item. It is assumed that both
    items are of the same type.
5272 5273 5274 5275 5276 5277 5278 5279 5280

  RETURN
    TRUE    Referenced item is equal to given item
    FALSE   otherwise
*/


bool Item_direct_view_ref::eq(const Item *item, bool binary_cmp) const
{
5281 5282 5283 5284 5285 5286
  if (item->type() == REF_ITEM)
  {
    Item_ref *item_ref= (Item_ref*) item;
    if (item_ref->ref_type() == VIEW_REF)
    {
      Item *item_ref_ref= *(item_ref->ref);
igor@rurik.mysql.com's avatar
igor@rurik.mysql.com committed
5287 5288
      DBUG_ASSERT((*ref)->real_item()->type() == 
                  item_ref_ref->real_item()->type());
5289
      return ((*ref)->real_item() == item_ref_ref->real_item());
5290 5291 5292
    }
  }
  return FALSE;
5293
}
5294

hf@deer.mysql.r18.ru's avatar
SCRUM  
hf@deer.mysql.r18.ru committed
5295 5296
bool Item_default_value::eq(const Item *item, bool binary_cmp) const
{
hf@deer.mysql.r18.ru's avatar
SCRUM  
hf@deer.mysql.r18.ru committed
5297
  return item->type() == DEFAULT_VALUE_ITEM && 
hf@deer.mysql.r18.ru's avatar
SCRUM  
hf@deer.mysql.r18.ru committed
5298 5299 5300
    ((Item_default_value *)item)->arg->eq(arg, binary_cmp);
}

5301

5302
bool Item_default_value::fix_fields(THD *thd, Item **items)
hf@deer.mysql.r18.ru's avatar
SCRUM  
hf@deer.mysql.r18.ru committed
5303
{
5304
  Item *real_arg;
5305 5306
  Item_field *field_arg;
  Field *def_field;
5307
  DBUG_ASSERT(fixed == 0);
5308

hf@deer.mysql.r18.ru's avatar
SCRUM  
hf@deer.mysql.r18.ru committed
5309
  if (!arg)
5310 5311
  {
    fixed= 1;
5312
    return FALSE;
5313
  }
5314 5315 5316
  if (!arg->fixed && arg->fix_fields(thd, &arg))
    goto error;

5317

5318 5319
  real_arg= arg->real_item();
  if (real_arg->type() != FIELD_ITEM)
hf@deer.mysql.r18.ru's avatar
SCRUM  
hf@deer.mysql.r18.ru committed
5320
  {
5321
    my_error(ER_NO_DEFAULT_FOR_FIELD, MYF(0), arg->name);
5322
    goto error;
hf@deer.mysql.r18.ru's avatar
SCRUM  
hf@deer.mysql.r18.ru committed
5323
  }
5324

5325
  field_arg= (Item_field *)real_arg;
5326 5327
  if (field_arg->field->flags & NO_DEFAULT_VALUE_FLAG)
  {
5328
    my_error(ER_NO_DEFAULT_FOR_FIELD, MYF(0), field_arg->field->field_name);
5329
    goto error;
5330 5331
  }
  if (!(def_field= (Field*) sql_alloc(field_arg->field->size_of())))
5332
    goto error;
hf@deer.mysql.r18.ru's avatar
SCRUM  
hf@deer.mysql.r18.ru committed
5333
  memcpy(def_field, field_arg->field, field_arg->field->size_of());
5334
  def_field->move_field(def_field->table->s->default_values -
5335
                        def_field->table->record[0]);
hf@deer.mysql.r18.ru's avatar
SCRUM  
hf@deer.mysql.r18.ru committed
5336
  set_field(def_field);
5337
  return FALSE;
5338 5339 5340 5341

error:
  context->process_error(thd);
  return TRUE;
hf@deer.mysql.r18.ru's avatar
SCRUM  
hf@deer.mysql.r18.ru committed
5342 5343
}

5344

hf@deer.mysql.r18.ru's avatar
SCRUM  
hf@deer.mysql.r18.ru committed
5345 5346
void Item_default_value::print(String *str)
{
hf@deer.mysql.r18.ru's avatar
SCRUM  
hf@deer.mysql.r18.ru committed
5347 5348
  if (!arg)
  {
5349
    str->append(STRING_WITH_LEN("default"));
hf@deer.mysql.r18.ru's avatar
SCRUM  
hf@deer.mysql.r18.ru committed
5350
    return;
hf@deer.mysql.r18.ru's avatar
SCRUM  
hf@deer.mysql.r18.ru committed
5351
  }
5352
  str->append(STRING_WITH_LEN("default("));
hf@deer.mysql.r18.ru's avatar
SCRUM  
hf@deer.mysql.r18.ru committed
5353 5354 5355
  arg->print(str);
  str->append(')');
}
5356

5357 5358 5359 5360 5361 5362 5363

int Item_default_value::save_in_field(Field *field_arg, bool no_conversions)
{
  if (!arg)
  {
    if (field_arg->flags & NO_DEFAULT_VALUE_FLAG)
    {
5364 5365
      if (context->error_processor == &view_error_processor)
      {
bell@sanja.is.com.ua's avatar
bell@sanja.is.com.ua committed
5366
        TABLE_LIST *view= cached_table->top_table();
5367 5368 5369 5370 5371 5372 5373 5374 5375 5376 5377 5378 5379 5380 5381
        push_warning_printf(field_arg->table->in_use,
                            MYSQL_ERROR::WARN_LEVEL_WARN,
                            ER_NO_DEFAULT_FOR_VIEW_FIELD,
                            ER(ER_NO_DEFAULT_FOR_VIEW_FIELD),
                            view->view_db.str,
                            view->view_name.str);
      }
      else
      {
        push_warning_printf(field_arg->table->in_use,
                            MYSQL_ERROR::WARN_LEVEL_WARN,
                            ER_NO_DEFAULT_FOR_FIELD,
                            ER(ER_NO_DEFAULT_FOR_FIELD),
                            field_arg->field_name);
      }
5382
      field_arg->set_default();
5383 5384 5385 5386 5387 5388 5389 5390 5391
      return 1;
    }
    field_arg->set_default();
    return 0;
  }
  return Item_field::save_in_field(field_arg, no_conversions);
}


5392
/* 
5393 5394
  This method like the walk method traverses the item tree, but at the
  same time it can replace some nodes in the tree
5395
*/ 
5396

5397 5398 5399 5400 5401 5402 5403 5404 5405 5406 5407 5408 5409 5410 5411 5412 5413 5414 5415 5416
Item *Item_default_value::transform(Item_transformer transformer, byte *args)
{
  DBUG_ASSERT(!current_thd->is_stmt_prepare());

  Item *new_item= arg->transform(transformer, args);
  if (!new_item)
    return 0;

  /*
    THD::change_item_tree() should be called only if the tree was
    really transformed, i.e. when a new item has been created.
    Otherwise we'll be allocating a lot of unnecessary memory for
    change records at each execution.
  */
  if (arg != new_item)
    current_thd->change_item_tree(&arg, new_item);
  return (this->*transformer)(args);
}


5417 5418 5419 5420 5421 5422 5423
bool Item_insert_value::eq(const Item *item, bool binary_cmp) const
{
  return item->type() == INSERT_VALUE_ITEM &&
    ((Item_default_value *)item)->arg->eq(arg, binary_cmp);
}


5424
bool Item_insert_value::fix_fields(THD *thd, Item **items)
5425
{
5426
  DBUG_ASSERT(fixed == 0);
5427
  /* We should only check that arg is in first table */
5428
  if (!arg->fixed)
5429
  {
5430 5431 5432 5433
    bool res;
    st_table_list *orig_next_table= context->last_name_resolution_table;
    context->last_name_resolution_table= context->first_name_resolution_table;
    res= arg->fix_fields(thd, &arg);
5434
    context->last_name_resolution_table= orig_next_table;
5435 5436
    if (res)
      return TRUE;
5437
  }
5438

5439 5440 5441 5442 5443
  if (arg->type() == REF_ITEM)
  {
    Item_ref *ref= (Item_ref *)arg;
    if (ref->ref[0]->type() != FIELD_ITEM)
    {
5444
      my_error(ER_BAD_FIELD_ERROR, MYF(0), "", "VALUES() function");
5445
      return TRUE;
5446 5447 5448
    }
    arg= ref->ref[0];
  }
5449 5450 5451 5452 5453 5454
  /*
    According to our SQL grammar, VALUES() function can reference
    only to a column.
  */
  DBUG_ASSERT(arg->type() == FIELD_ITEM);

5455
  Item_field *field_arg= (Item_field *)arg;
5456

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  if (field_arg->field->table->insert_values)
  {
    Field *def_field= (Field*) sql_alloc(field_arg->field->size_of());
    if (!def_field)
5461
      return TRUE;
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    memcpy(def_field, field_arg->field, field_arg->field->size_of());
    def_field->move_field(def_field->table->insert_values -
                          def_field->table->record[0]);
    set_field(def_field);
  }
  else
  {
5469
    Field *tmp_field= field_arg->field;
5470
    /* charset doesn't matter here, it's to avoid sigsegv only */
5471 5472
    set_field(new Field_null(0, 0, Field::NONE, tmp_field->field_name,
			     tmp_field->table, &my_charset_bin));
5473
  }
5474
  return FALSE;
5475 5476 5477 5478
}

void Item_insert_value::print(String *str)
{
5479
  str->append(STRING_WITH_LEN("values("));
5480 5481 5482 5483
  arg->print(str);
  str->append(')');
}

5484 5485

/*
5486 5487
  Find index of Field object which will be appropriate for item
  representing field of row being changed in trigger.
5488 5489 5490 5491 5492

  SYNOPSIS
    setup_field()
      thd   - current thread context
      table - table of trigger (and where we looking for fields)
5493
      table_grant_info - GRANT_INFO of the subject table
5494 5495 5496

  NOTE
    This function does almost the same as fix_fields() for Item_field
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    but is invoked right after trigger definition parsing. Since at
    this stage we can't say exactly what Field object (corresponding
    to TABLE::record[0] or TABLE::record[1]) should be bound to this
    Item, we only find out index of the Field and then select concrete
    Field object in fix_fields() (by that time Table_trigger_list::old_field/
    new_field should point to proper array of Fields).
    It also binds Item_trigger_field to Table_triggers_list object for
    table of trigger which uses this item.
5505
*/
5506

5507 5508
void Item_trigger_field::setup_field(THD *thd, TABLE *table,
                                     GRANT_INFO *table_grant_info)
5509
{
5510 5511 5512 5513 5514 5515 5516
  /*
    There is no sense in marking fields used by trigger with current value
    of THD::query_id since it is completely unrelated to the THD::query_id
    value for statements which will invoke trigger. So instead we use
    Table_triggers_list::mark_fields_used() method which is called during
    execution of these statements.
  */
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  bool save_set_query_id= thd->set_query_id;
  thd->set_query_id= 0;
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  /*
    Try to find field by its name and if it will be found
    set field_idx properly.
  */
5523
  (void)find_field_in_table(thd, table, field_name, (uint) strlen(field_name),
5524
                            0, &field_idx);
5525
  thd->set_query_id= save_set_query_id;
5526
  triggers= table->triggers;
5527
  table_grants= table_grant_info;
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}


bool Item_trigger_field::eq(const Item *item, bool binary_cmp) const
{
  return item->type() == TRIGGER_FIELD_ITEM &&
         row_version == ((Item_trigger_field *)item)->row_version &&
         !my_strcasecmp(system_charset_info, field_name,
                        ((Item_trigger_field *)item)->field_name);
}


5540
void Item_trigger_field::set_required_privilege(bool rw)
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{
  /*
    Require SELECT and UPDATE privilege if this field will be read and
    set, and only UPDATE privilege for setting the field.
  */
  want_privilege= (rw ? SELECT_ACL | UPDATE_ACL : UPDATE_ACL);
}


5550
bool Item_trigger_field::set_value(THD *thd, sp_rcontext */*ctx*/, Item **it)
5551
{
5552
  Item *item= sp_prepare_func_item(thd, it);
5553 5554 5555 5556 5557 5558

  return (!item || (!fixed && fix_fields(thd, 0)) ||
          (item->save_in_field(field, 0) < 0));
}


5559
bool Item_trigger_field::fix_fields(THD *thd, Item **items)
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{
  /*
    Since trigger is object tightly associated with TABLE object most
    of its set up can be performed during trigger loading i.e. trigger
    parsing! So we have little to do in fix_fields. :)
  */
5566

5567
  DBUG_ASSERT(fixed == 0);
5568

5569 5570
  /* Set field. */

5571
  if (field_idx != (uint)-1)
5572
  {
5573 5574 5575 5576 5577 5578 5579 5580
#ifndef NO_EMBEDDED_ACCESS_CHECKS
    /*
      Check access privileges for the subject table. We check privileges only
      in runtime.
    */

    if (table_grants)
    {
5581
      table_grants->want_privilege= want_privilege;
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      if (check_grant_column(thd, table_grants, triggers->table->s->db,
                             triggers->table->s->table_name, field_name,
                             strlen(field_name), thd->security_ctx))
        return TRUE;
    }
#endif // NO_EMBEDDED_ACCESS_CHECKS

5590 5591
    field= (row_version == OLD_ROW) ? triggers->old_field[field_idx] :
                                      triggers->new_field[field_idx];
5592 5593
    set_field(field);
    fixed= 1;
5594
    return FALSE;
5595 5596 5597 5598
  }

  my_error(ER_BAD_FIELD_ERROR, MYF(0), field_name,
           (row_version == NEW_ROW) ? "NEW" : "OLD");
5599
  return TRUE;
5600 5601 5602 5603 5604 5605 5606 5607 5608 5609 5610 5611 5612
}


void Item_trigger_field::print(String *str)
{
  str->append((row_version == NEW_ROW) ? "NEW" : "OLD", 3);
  str->append('.');
  str->append(field_name);
}


void Item_trigger_field::cleanup()
{
5613
  want_privilege= original_privilege;
5614 5615 5616 5617 5618 5619 5620 5621
  /*
    Since special nature of Item_trigger_field we should not do most of
    things from Item_field::cleanup() or Item_ident::cleanup() here.
  */
  Item::cleanup();
}


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5622
/*
5623 5624
  If item is a const function, calculate it and return a const item
  The original item is freed if not returned
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*/

Item_result item_cmp_type(Item_result a,Item_result b)
{
  if (a == STRING_RESULT && b == STRING_RESULT)
    return STRING_RESULT;
5631
  if (a == INT_RESULT && b == INT_RESULT)
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5632
    return INT_RESULT;
5633 5634
  else if (a == ROW_RESULT || b == ROW_RESULT)
    return ROW_RESULT;
5635 5636 5637
  if ((a == INT_RESULT || a == DECIMAL_RESULT) &&
      (b == INT_RESULT || b == DECIMAL_RESULT))
    return DECIMAL_RESULT;
5638
  return REAL_RESULT;
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5639 5640 5641
}


5642
void resolve_const_item(THD *thd, Item **ref, Item *comp_item)
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5643
{
5644
  Item *item= *ref;
5645
  Item *new_item= NULL;
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5646
  if (item->basic_const_item())
5647
    return;                                     // Can't be better
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5648 5649 5650 5651
  Item_result res_type=item_cmp_type(comp_item->result_type(),
				     item->result_type());
  char *name=item->name;			// Alloced by sql_alloc

5652
  switch (res_type) {
5653
  case STRING_RESULT:
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5654 5655
  {
    char buff[MAX_FIELD_WIDTH];
5656
    String tmp(buff,sizeof(buff),&my_charset_bin),*result;
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5657 5658
    result=item->val_str(&tmp);
    if (item->null_value)
5659 5660 5661 5662 5663 5664 5665
      new_item= new Item_null(name);
    else
    {
      uint length= result->length();
      char *tmp_str= sql_strmake(result->ptr(), length);
      new_item= new Item_string(name, tmp_str, length, result->charset());
    }
5666
    break;
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5667
  }
5668
  case INT_RESULT:
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  {
    longlong result=item->val_int();
    uint length=item->max_length;
    bool null_value=item->null_value;
5673 5674
    new_item= (null_value ? (Item*) new Item_null(name) :
               (Item*) new Item_int(name, result, length));
5675
    break;
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5676
  }
5677
  case ROW_RESULT:
5678
  if (item->type() == Item::ROW_ITEM && comp_item->type() == Item::ROW_ITEM)
5679
  {
5680 5681 5682 5683 5684 5685 5686 5687
    /*
      Substitute constants only in Item_rows. Don't affect other Items
      with ROW_RESULT (eg Item_singlerow_subselect).

      For such Items more optimal is to detect if it is constant and replace
      it with Item_row. This would optimize queries like this:
      SELECT * FROM t1 WHERE (a,b) = (SELECT a,b FROM t2 LIMIT 1);
    */
5688 5689 5690
    Item_row *item_row= (Item_row*) item;
    Item_row *comp_item_row= (Item_row*) comp_item;
    uint col;
5691 5692 5693
    new_item= 0;
    /*
      If item and comp_item are both Item_rows and have same number of cols
5694 5695 5696
      then process items in Item_row one by one.
      We can't ignore NULL values here as this item may be used with <=>, in
      which case NULL's are significant.
5697
    */
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    DBUG_ASSERT(item->result_type() == comp_item->result_type());
    DBUG_ASSERT(item_row->cols() == comp_item_row->cols());
    col= item_row->cols();
    while (col-- > 0)
      resolve_const_item(thd, item_row->addr(col), comp_item_row->el(col));
5703
    break;
5704
  }
5705
  /* Fallthrough */
5706
  case REAL_RESULT:
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5707
  {						// It must REAL_RESULT
5708
    double result= item->val_real();
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5709 5710
    uint length=item->max_length,decimals=item->decimals;
    bool null_value=item->null_value;
5711
    new_item= (null_value ? (Item*) new Item_null(name) : (Item*)
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               new Item_float(name, result, decimals, length));
    break;
  }
  case DECIMAL_RESULT:
  {
    my_decimal decimal_value;
    my_decimal *result= item->val_decimal(&decimal_value);
    uint length= item->max_length, decimals= item->decimals;
    bool null_value= item->null_value;
    new_item= (null_value ?
               (Item*) new Item_null(name) :
               (Item*) new Item_decimal(name, result, length, decimals));
    break;
  }
  default:
    DBUG_ASSERT(0);
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5728
  }
5729 5730
  if (new_item)
    thd->change_item_tree(ref, new_item);
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}

/*
  Return true if the value stored in the field is equal to the const item
  We need to use this on the range optimizer because in some cases
  we can't store the value in the field without some precision/character loss.
*/

bool field_is_equal_to_item(Field *field,Item *item)
{

  Item_result res_type=item_cmp_type(field->result_type(),
				     item->result_type());
  if (res_type == STRING_RESULT)
  {
    char item_buff[MAX_FIELD_WIDTH];
    char field_buff[MAX_FIELD_WIDTH];
5748 5749
    String item_tmp(item_buff,sizeof(item_buff),&my_charset_bin),*item_result;
    String field_tmp(field_buff,sizeof(field_buff),&my_charset_bin);
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5750 5751 5752
    item_result=item->val_str(&item_tmp);
    if (item->null_value)
      return 1;					// This must be true
5753
    field->val_str(&field_tmp);
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5754
    return !stringcmp(&field_tmp,item_result);
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5755 5756 5757
  }
  if (res_type == INT_RESULT)
    return 1;					// Both where of type int
5758 5759 5760 5761 5762 5763 5764 5765 5766 5767
  if (res_type == DECIMAL_RESULT)
  {
    my_decimal item_buf, *item_val,
               field_buf, *field_val;
    item_val= item->val_decimal(&item_buf);
    if (item->null_value)
      return 1;					// This must be true
    field_val= field->val_decimal(&field_buf);
    return !my_decimal_cmp(item_val, field_val);
  }
5768
  double result= item->val_real();
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5769 5770 5771 5772 5773
  if (item->null_value)
    return 1;
  return result == field->val_real();
}

5774 5775
Item_cache* Item_cache::get_cache(Item_result type)
{
5776
  switch (type) {
5777 5778 5779 5780
  case INT_RESULT:
    return new Item_cache_int();
  case REAL_RESULT:
    return new Item_cache_real();
5781 5782
  case DECIMAL_RESULT:
    return new Item_cache_decimal();
5783 5784
  case STRING_RESULT:
    return new Item_cache_str();
5785 5786
  case ROW_RESULT:
    return new Item_cache_row();
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  default:
    // should never be in real life
    DBUG_ASSERT(0);
    return 0;
  }
}

5794 5795 5796

void Item_cache::print(String *str)
{
5797
  str->append(STRING_WITH_LEN("<cache>("));
5798 5799 5800 5801 5802 5803 5804 5805 5806 5807 5808 5809
  if (example)
    example->print(str);
  else
    Item::print(str);
  str->append(')');
}


void Item_cache_int::store(Item *item)
{
  value= item->val_int_result();
  null_value= item->null_value;
5810 5811 5812 5813 5814 5815 5816 5817 5818 5819 5820 5821 5822 5823 5824 5825 5826
  unsigned_flag= item->unsigned_flag;
}


String *Item_cache_int::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  str->set(value, default_charset());
  return str;
}


my_decimal *Item_cache_int::val_decimal(my_decimal *decimal_val)
{
  DBUG_ASSERT(fixed == 1);
  int2my_decimal(E_DEC_FATAL_ERROR, value, unsigned_flag, decimal_val);
  return decimal_val;
5827 5828 5829 5830 5831 5832 5833 5834 5835 5836
}


void Item_cache_real::store(Item *item)
{
  value= item->val_result();
  null_value= item->null_value;
}


5837 5838 5839
longlong Item_cache_real::val_int()
{
  DBUG_ASSERT(fixed == 1);
5840
  return (longlong) rint(value);
5841 5842 5843 5844 5845 5846 5847 5848 5849 5850 5851 5852 5853 5854 5855 5856 5857 5858 5859 5860 5861 5862
}


String* Item_cache_real::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
  str->set(value, decimals, default_charset());
  return str;
}


my_decimal *Item_cache_real::val_decimal(my_decimal *decimal_val)
{
  DBUG_ASSERT(fixed == 1);
  double2my_decimal(E_DEC_FATAL_ERROR, value, decimal_val);
  return decimal_val;
}


void Item_cache_decimal::store(Item *item)
{
  my_decimal *val= item->val_decimal_result(&decimal_value);
5863
  if (!(null_value= item->null_value) && val != &decimal_value)
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    my_decimal2decimal(val, &decimal_value);
}

double Item_cache_decimal::val_real()
{
  DBUG_ASSERT(fixed);
  double res;
  my_decimal2double(E_DEC_FATAL_ERROR, &decimal_value, &res);
  return res;
}

longlong Item_cache_decimal::val_int()
{
  DBUG_ASSERT(fixed);
  longlong res;
  my_decimal2int(E_DEC_FATAL_ERROR, &decimal_value, unsigned_flag, &res);
  return res;
}

String* Item_cache_decimal::val_str(String *str)
{
  DBUG_ASSERT(fixed);
  my_decimal_round(E_DEC_FATAL_ERROR, &decimal_value, decimals, FALSE,
                   &decimal_value);
  my_decimal2string(E_DEC_FATAL_ERROR, &decimal_value, 0, 0, 0, str);
  return str;
}

my_decimal *Item_cache_decimal::val_decimal(my_decimal *val)
{
  DBUG_ASSERT(fixed);
  return &decimal_value;
}


5899 5900
void Item_cache_str::store(Item *item)
{
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5901
  value_buff.set(buffer, sizeof(buffer), item->collation.collation);
5902
  value= item->str_result(&value_buff);
5903 5904
  if ((null_value= item->null_value))
    value= 0;
5905
  else if (value != &value_buff)
5906 5907 5908 5909 5910 5911 5912 5913 5914
  {
    /*
      We copy string value to avoid changing value if 'item' is table field
      in queries like following (where t1.c is varchar):
      select a, 
             (select a,b,c from t1 where t1.a=t2.a) = ROW(a,2,'a'),
             (select c from t1 where a=t2.a)
        from t2;
    */
5915 5916
    value_buff.copy(*value);
    value= &value_buff;
5917 5918
  }
}
5919

5920
double Item_cache_str::val_real()
5921 5922
{
  DBUG_ASSERT(fixed == 1);
5923 5924
  int err_not_used;
  char *end_not_used;
5925
  if (value)
5926
    return my_strntod(value->charset(), (char*) value->ptr(),
5927 5928
		      value->length(), &end_not_used, &err_not_used);
  return (double) 0;
5929
}
5930 5931


5932 5933
longlong Item_cache_str::val_int()
{
5934
  DBUG_ASSERT(fixed == 1);
5935
  int err;
5936 5937
  if (value)
    return my_strntoll(value->charset(), value->ptr(),
5938
		       value->length(), 10, (char**) 0, &err);
5939 5940 5941
  else
    return (longlong)0;
}
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5942

5943 5944 5945 5946 5947 5948 5949 5950 5951 5952
my_decimal *Item_cache_str::val_decimal(my_decimal *decimal_val)
{
  DBUG_ASSERT(fixed == 1);
  if (value)
    string2my_decimal(E_DEC_FATAL_ERROR, value, decimal_val);
  else
    decimal_val= 0;
  return decimal_val;
}

5953

5954 5955
bool Item_cache_row::allocate(uint num)
{
5956
  item_count= num;
5957
  THD *thd= current_thd;
5958 5959
  return (!(values= 
	    (Item_cache **) thd->calloc(sizeof(Item_cache *)*item_count)));
5960 5961
}

5962

5963 5964
bool Item_cache_row::setup(Item * item)
{
5965
  example= item;
5966 5967
  if (!values && allocate(item->cols()))
    return 1;
5968
  for (uint i= 0; i < item_count; i++)
5969
  {
5970
    Item *el= item->el(i);
5971 5972
    Item_cache *tmp;
    if (!(tmp= values[i]= Item_cache::get_cache(el->result_type())))
5973
      return 1;
5974
    tmp->setup(el);
5975 5976 5977 5978
  }
  return 0;
}

5979

5980 5981 5982 5983
void Item_cache_row::store(Item * item)
{
  null_value= 0;
  item->bring_value();
5984
  for (uint i= 0; i < item_count; i++)
5985 5986 5987 5988 5989 5990
  {
    values[i]->store(item->el(i));
    null_value|= values[i]->null_value;
  }
}

5991

5992 5993 5994 5995 5996
void Item_cache_row::illegal_method_call(const char *method)
{
  DBUG_ENTER("Item_cache_row::illegal_method_call");
  DBUG_PRINT("error", ("!!! %s method was called for row item", method));
  DBUG_ASSERT(0);
5997
  my_error(ER_OPERAND_COLUMNS, MYF(0), 1);
5998 5999 6000
  DBUG_VOID_RETURN;
}

6001

6002 6003
bool Item_cache_row::check_cols(uint c)
{
6004
  if (c != item_count)
6005
  {
6006
    my_error(ER_OPERAND_COLUMNS, MYF(0), c);
6007 6008 6009 6010 6011
    return 1;
  }
  return 0;
}

6012

6013 6014
bool Item_cache_row::null_inside()
{
6015
  for (uint i= 0; i < item_count; i++)
6016 6017 6018 6019 6020 6021 6022 6023 6024 6025 6026 6027 6028 6029 6030 6031
  {
    if (values[i]->cols() > 1)
    {
      if (values[i]->null_inside())
	return 1;
    }
    else
    {
      values[i]->val_int();
      if (values[i]->null_value)
	return 1;
    }
  }
  return 0;
}

6032

6033 6034
void Item_cache_row::bring_value()
{
6035
  for (uint i= 0; i < item_count; i++)
6036 6037 6038
    values[i]->bring_value();
  return;
}
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6039

6040

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Item_type_holder::Item_type_holder(THD *thd, Item *item)
  :Item(thd, item), enum_set_typelib(0), fld_type(get_real_type(item))
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{
  DBUG_ASSERT(item->fixed);
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  max_length= display_length(item);
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  maybe_null= item->maybe_null;
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  collation.set(item->collation);
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  get_full_info(item);
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  /* fix variable decimals which always is NOT_FIXED_DEC */
  if (Field::result_merge_type(fld_type) == INT_RESULT)
    decimals= 0;
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  prev_decimal_int_part= item->decimal_int_part();
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}


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/*
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  Return expression type of Item_type_holder
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  SYNOPSIS
6061
    Item_type_holder::result_type()
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  RETURN
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     Item_result (type of internal MySQL expression result)
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*/

6067
Item_result Item_type_holder::result_type() const
6068
{
6069
  return Field::result_merge_type(fld_type);
6070
}
6071

6072

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/*
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  Find real field type of item
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  SYNOPSIS
6077
    Item_type_holder::get_real_type()
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  RETURN
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    type of field which should be created to store item value
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*/

6083
enum_field_types Item_type_holder::get_real_type(Item *item)
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{
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  switch(item->type())
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  {
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  case FIELD_ITEM:
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  {
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    /*
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      Item_fields::field_type ask Field_type() but sometimes field return
      a different type, like for enum/set, so we need to ask real type.
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    */
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    Field *field= ((Item_field *) item)->field;
    enum_field_types type= field->real_type();
    /* work around about varchar type field detection */
    if (type == MYSQL_TYPE_STRING && field->type() == MYSQL_TYPE_VAR_STRING)
      return MYSQL_TYPE_VAR_STRING;
    return type;
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  }
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  case SUM_FUNC_ITEM:
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  {
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    /*
      Argument of aggregate function sometimes should be asked about field
      type
    */
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    Item_sum *item_sum= (Item_sum *) item;
    if (item_sum->keep_field_type())
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      return get_real_type(item_sum->args[0]);
    break;
  }
  case FUNC_ITEM:
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    if (((Item_func *) item)->functype() == Item_func::GUSERVAR_FUNC)
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    {
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      /*
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        There are work around of problem with changing variable type on the
        fly and variable always report "string" as field type to get
        acceptable information for client in send_field, so we make field
        type from expression type.
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      */
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      switch (item->result_type()) {
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      case STRING_RESULT:
        return MYSQL_TYPE_VAR_STRING;
      case INT_RESULT:
        return MYSQL_TYPE_LONGLONG;
      case REAL_RESULT:
        return MYSQL_TYPE_DOUBLE;
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      case DECIMAL_RESULT:
        return MYSQL_TYPE_NEWDECIMAL;
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      case ROW_RESULT:
      default:
        DBUG_ASSERT(0);
        return MYSQL_TYPE_VAR_STRING;
      }
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    }
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    break;
  default:
    break;
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  }
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  return item->field_type();
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}

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/*
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  Find field type which can carry current Item_type_holder type and
  type of given Item.
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  SYNOPSIS
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    Item_type_holder::join_types()
    thd     thread handler
    item    given item to join its parameters with this item ones
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  RETURN
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    TRUE   error - types are incompatible
    FALSE  OK
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*/

6156
bool Item_type_holder::join_types(THD *thd, Item *item)
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{
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  uint max_length_orig= max_length;
  uint decimals_orig= decimals;
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  DBUG_ENTER("Item_type_holder::join_types");
  DBUG_PRINT("info:", ("was type %d len %d, dec %d name %s",
                       fld_type, max_length, decimals,
                       (name ? name : "<NULL>")));
  DBUG_PRINT("info:", ("in type %d len %d, dec %d",
                       get_real_type(item),
                       item->max_length, item->decimals));
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  fld_type= Field::field_type_merge(fld_type, get_real_type(item));
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  {
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    int item_decimals= item->decimals;
    /* fix variable decimals which always is NOT_FIXED_DEC */
    if (Field::result_merge_type(fld_type) == INT_RESULT)
      item_decimals= 0;
    decimals= max(decimals, item_decimals);
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  }
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  if (Field::result_merge_type(fld_type) == DECIMAL_RESULT)
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  {
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    decimals= min(max(decimals, item->decimals), DECIMAL_MAX_SCALE);
    int precision= min(max(prev_decimal_int_part, item->decimal_int_part())
                       + decimals, DECIMAL_MAX_PRECISION);
    unsigned_flag&= item->unsigned_flag;
    max_length= my_decimal_precision_to_length(precision, decimals,
                                               unsigned_flag);
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  }
6184

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  switch (Field::result_merge_type(fld_type))
  {
  case STRING_RESULT:
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  {
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    const char *old_cs, *old_derivation;
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    uint32 old_max_chars= max_length / collation.collation->mbmaxlen;
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    old_cs= collation.collation->name;
    old_derivation= collation.derivation_name();
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    if (collation.aggregate(item->collation, MY_COLL_ALLOW_CONV))
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    {
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      my_error(ER_CANT_AGGREGATE_2COLLATIONS, MYF(0),
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	       old_cs, old_derivation,
	       item->collation.collation->name,
	       item->collation.derivation_name(),
	       "UNION");
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      DBUG_RETURN(TRUE);
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    }
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    /*
      To figure out max_length, we have to take into account possible
      expansion of the size of the values because of character set
      conversions.
     */
    max_length= max(old_max_chars * collation.collation->mbmaxlen,
                    display_length(item) / item->collation.collation->mbmaxlen *
                    collation.collation->mbmaxlen);
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    break;
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  }
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  case REAL_RESULT:
  {
    if (decimals != NOT_FIXED_DEC)
    {
      int delta1= max_length_orig - decimals_orig;
      int delta2= item->max_length - item->decimals;
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      if (fld_type == MYSQL_TYPE_DECIMAL)
        max_length= max(delta1, delta2) + decimals;
      else
        max_length= min(max(delta1, delta2) + decimals,
                        (fld_type == MYSQL_TYPE_FLOAT) ? FLT_DIG+6 : DBL_DIG+7);
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    }
    else
      max_length= (fld_type == MYSQL_TYPE_FLOAT) ? FLT_DIG+6 : DBL_DIG+7;
    break;
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  }
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  default:
    max_length= max(max_length, display_length(item));
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  };
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  maybe_null|= item->maybe_null;
  get_full_info(item);
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  /* Remember decimal integer part to be used in DECIMAL_RESULT handleng */
  prev_decimal_int_part= decimal_int_part();
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  DBUG_PRINT("info", ("become type: %d  len: %u  dec: %u",
                      (int) fld_type, max_length, (uint) decimals));
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  DBUG_RETURN(FALSE);
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}

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/*
  Calculate lenth for merging result for given Item type
6243

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  SYNOPSIS
    Item_type_holder::real_length()
    item  Item for lrngth detection
6247

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  RETURN
    length
*/
6251

6252
uint32 Item_type_holder::display_length(Item *item)
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{
  if (item->type() == Item::FIELD_ITEM)
6255
    return ((Item_field *)item)->max_disp_length();
6256

6257
  switch (item->field_type())
6258
  {
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  case MYSQL_TYPE_DECIMAL:
  case MYSQL_TYPE_TIMESTAMP:
  case MYSQL_TYPE_DATE:
  case MYSQL_TYPE_TIME:
  case MYSQL_TYPE_DATETIME:
  case MYSQL_TYPE_YEAR:
  case MYSQL_TYPE_NEWDATE:
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  case MYSQL_TYPE_VARCHAR:
  case MYSQL_TYPE_BIT:
  case MYSQL_TYPE_NEWDECIMAL:
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  case MYSQL_TYPE_ENUM:
  case MYSQL_TYPE_SET:
  case MYSQL_TYPE_TINY_BLOB:
  case MYSQL_TYPE_MEDIUM_BLOB:
  case MYSQL_TYPE_LONG_BLOB:
  case MYSQL_TYPE_BLOB:
  case MYSQL_TYPE_VAR_STRING:
  case MYSQL_TYPE_STRING:
  case MYSQL_TYPE_GEOMETRY:
6278
    return item->max_length;
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  case MYSQL_TYPE_TINY:
    return 4;
  case MYSQL_TYPE_SHORT:
    return 6;
  case MYSQL_TYPE_LONG:
    return 11;
  case MYSQL_TYPE_FLOAT:
    return 25;
  case MYSQL_TYPE_DOUBLE:
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    return 53;
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  case MYSQL_TYPE_NULL:
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    return 0;
6291
  case MYSQL_TYPE_LONGLONG:
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    return 20;
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  case MYSQL_TYPE_INT24:
    return 8;
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  default:
    DBUG_ASSERT(0); // we should never go there
    return 0;
  }
}
6300

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/*
  Make temporary table field according collected information about type
  of UNION result

  SYNOPSIS
    Item_type_holder::make_field_by_type()
    table  temporary table for which we create fields

  RETURN
    created field
*/

Field *Item_type_holder::make_field_by_type(TABLE *table)
{
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  /*
    The field functions defines a field to be not null if null_ptr is not 0
  */
  uchar *null_ptr= maybe_null ? (uchar*) "" : 0;
  switch (fld_type)
6321
  {
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  case MYSQL_TYPE_ENUM:
6323
    DBUG_ASSERT(enum_set_typelib);
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    return new Field_enum((char *) 0, max_length, null_ptr, 0,
                          Field::NONE, name,
                          table, get_enum_pack_length(enum_set_typelib->count),
                          enum_set_typelib, collation.collation);
  case MYSQL_TYPE_SET:
    DBUG_ASSERT(enum_set_typelib);
    return new Field_set((char *) 0, max_length, null_ptr, 0,
                         Field::NONE, name,
                         table, get_set_pack_length(enum_set_typelib->count),
                         enum_set_typelib, collation.collation);
  default:
    break;
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  }
  return tmp_table_field_from_field_type(table);
}


/*
  Get full information from Item about enum/set fields to be able to create
  them later

  SYNOPSIS
    Item_type_holder::get_full_info
    item    Item for information collection
*/
void Item_type_holder::get_full_info(Item *item)
{
  if (fld_type == MYSQL_TYPE_ENUM ||
      fld_type == MYSQL_TYPE_SET)
  {
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    if (item->type() == Item::SUM_FUNC_ITEM &&
        (((Item_sum*)item)->sum_func() == Item_sum::MAX_FUNC ||
         ((Item_sum*)item)->sum_func() == Item_sum::MIN_FUNC))
      item = ((Item_sum*)item)->args[0];
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    /*
6359 6360
      We can have enum/set type after merging only if we have one enum|set
      field (or MIN|MAX(enum|set field)) and number of NULL fields
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    */
    DBUG_ASSERT((enum_set_typelib &&
                 get_real_type(item) == MYSQL_TYPE_NULL) ||
                (!enum_set_typelib &&
                 item->type() == Item::FIELD_ITEM &&
                 (get_real_type(item) == MYSQL_TYPE_ENUM ||
                  get_real_type(item) == MYSQL_TYPE_SET) &&
                 ((Field_enum*)((Item_field *) item)->field)->typelib));
    if (!enum_set_typelib)
    {
      enum_set_typelib= ((Field_enum*)((Item_field *) item)->field)->typelib;
    }
  }
}


6377
double Item_type_holder::val_real()
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{
  DBUG_ASSERT(0); // should never be called
  return 0.0;
}


longlong Item_type_holder::val_int()
{
  DBUG_ASSERT(0); // should never be called
  return 0;
}

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my_decimal *Item_type_holder::val_decimal(my_decimal *)
{
  DBUG_ASSERT(0); // should never be called
  return 0;
}
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String *Item_type_holder::val_str(String*)
{
  DBUG_ASSERT(0); // should never be called
  return 0;
}

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void Item_result_field::cleanup()
{
  DBUG_ENTER("Item_result_field::cleanup()");
  Item::cleanup();
  result_field= 0;
  DBUG_VOID_RETURN;
}

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/*
  Dummy error processor used by default by Name_resolution_context

  SYNOPSIS
    dummy_error_processor()

  NOTE
    do nothing
*/

void dummy_error_processor(THD *thd, void *data)
{}

/*
  Wrapper of hide_view_error call for Name_resolution_context error processor

  SYNOPSIS
    view_error_processor()

  NOTE
    hide view underlying tables details in error messages
*/

void view_error_processor(THD *thd, void *data)
{
  ((TABLE_LIST *)data)->hide_view_error(thd);
}

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/*****************************************************************************
** Instantiate templates
*****************************************************************************/

6442
#ifdef HAVE_EXPLICIT_TEMPLATE_INSTANTIATION
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template class List<Item>;
template class List_iterator<Item>;
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template class List_iterator_fast<Item>;
6446
template class List_iterator_fast<Item_field>;
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template class List<List_item>;
#endif