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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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  /* 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)
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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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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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    /*
      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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  }
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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)) &&
           (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
void my_coll_agg_error(Item** args, uint count, const char *fname)
{
  if (count == 2)
    my_coll_agg_error(args[0]->collation, args[1]->collation, fname);
  else if (count == 3)
    my_coll_agg_error(args[0]->collation, args[1]->collation,
                      args[2]->collation, fname);
  else
    my_error(ER_CANT_AGGREGATE_NCOLLATIONS,MYF(0),fname);
}


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


/* 
  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)
*/

bool agg_item_charsets(DTCollation &coll, const char *fname,
                       Item **args, uint nargs, uint flags)
{
  Item **arg, **last, *safe_args[2];
  if (agg_item_collations(coll, fname, args, nargs, flags))
    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];
    safe_args[1]= args[1];
  }

  THD *thd= current_thd;
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  Query_arena *arena, backup;
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  bool res= FALSE;
  /*
    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->activate_stmt_arena_if_needed(&backup);
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  for (arg= args, last= args + nargs; arg < last; arg++)
  {
    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];
        args[1]= safe_args[1];
      }
      my_coll_agg_error(args, nargs, fname);
      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 && arena->is_conventional())
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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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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);
}

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// Constructor need to process subselect with temporary tables (see Item)
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Item_field::Item_field(THD *thd, Item_field *item)
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  :Item_ident(thd, item),
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   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);
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  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;
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  if (!table_name || !field_name)
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    return field_name ? field_name : name ? name : "tmp_field";
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  if (db_name && db_name[0])
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  {
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    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)
{
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  THD *thd= current_thd;
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  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)
  {
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    const char *nm= field_name ? field_name : name ? name : "tmp_field";
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    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)
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  {
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    if (!(cached_table && cached_table->belong_to_view &&
          cached_table->belong_to_view->compact_view_format))
    {
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      append_identifier(thd, str, d_name, (uint)strlen(d_name));
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      str->append('.');
    }
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    append_identifier(thd, str, t_name, (uint)strlen(t_name));
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    str->append('.');
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    append_identifier(thd, str, field_name, (uint)strlen(field_name));
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  }
  else
  {
    if (table_name[0])
    {
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      append_identifier(thd, str, t_name, (uint) strlen(t_name));
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      str->append('.');
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      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)
{
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  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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double Item_field::val_real()
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{
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  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()
{
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  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;
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  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;
}

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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;
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  switch (result_field->result_type()) {
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  case INT_RESULT:
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    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);
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    return 0;                                   // Shut up compiler
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  }
}


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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()
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{
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  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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  /*
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    We must prevent all charset conversions until data has been written
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    to the binary log.
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  */
  str_value.set_charset(&my_charset_bin);
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  collation.set(&my_charset_bin, DERIVATION_COERCIBLE);
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  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).
  */
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  DBUG_VOID_RETURN;
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}


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int Item_param::save_in_field(Field *field, bool no_conversions)
2446 2447
{
  field->set_notnull();
2448 2449 2450

  switch (state) {
  case INT_VALUE:
2451
    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);
2458
    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:
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    return set_field_to_null_with_conversions(field, no_conversions);
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  case NO_VALUE:
  default:
    DBUG_ASSERT(0);
2468
  }
2469
  return 1;
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}

2472

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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);
2485
}
2486

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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);
}


2499
double Item_param::val_real()
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{
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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.
    */
2525
    return ulonglong2double(TIME_to_ulonglong(&value.time));
2526
  case NULL_VALUE:
2527
    return 0.0;
2528
  default:
2529
    DBUG_ASSERT(0);
2530
  }
2531
  return 0.0;
2532 2533
} 

2534

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longlong Item_param::val_int() 
{ 
2537 2538
  switch (state) {
  case REAL_VALUE:
2539
    return (longlong) rint(value.real);
2540 2541
  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; 
2559
  default:
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    DBUG_ASSERT(0);
2561
  }
2562
  return 0;
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}

2565

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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:
2601
    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);
2607
    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;
2613 2614
  case TIME_VALUE:
  {
2615
    if (str->reserve(MAX_DATE_STRING_REP_LENGTH))
2616
      break;
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    str->length((uint) my_TIME_to_str(&value.time, (char*) str->ptr()));
    str->set_charset(&my_charset_bin);
2619
    return str;
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  }
  case NULL_VALUE:
    return NULL; 
2623
  default:
2624
    DBUG_ASSERT(0);
2625
  }
2626
  return str;
2627
}
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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.
2634 2635
*/

2636
const String *Item_param::query_val_str(String* str) const
2637
{
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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;
2650
  case TIME_VALUE:
2651
    {
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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 
      */
2658
      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++= '\'';
2665
      ptr+= (uint) my_TIME_to_str(&value.time, ptr);
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      *ptr++= '\'';
      str->length((uint32) (ptr - buf));
      break;
2669
    }
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  case STRING_VALUE:
  case LONG_DATA_VALUE:
2672
    {
2673
      str->length(0);
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      append_query_string(value.cs_info.character_set_client, &str_value, str);
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      break;
2676
    }
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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 !=
2703
        value.cs_info.character_set_of_placeholder)
2704 2705
    {
      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));
2747
  case REAL_VALUE:
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    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:
2782
    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
  {
2804
    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)
{
2828
  // 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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/*
2856
  Functions to convert item to field (for send_fields)
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*/

/* ARGSUSED */
2860
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());
2865
  fixed= 1;
2866
  return FALSE;
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}

2869
double Item_ref_null_helper::val_real()
2870
{
2871
  DBUG_ASSERT(fixed == 1);
2872
  double tmp= (*ref)->val_result();
2873
  owner->was_null|= null_value= (*ref)->null_value;
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  return tmp;
}
2876 2877


2878 2879
longlong Item_ref_null_helper::val_int()
{
2880
  DBUG_ASSERT(fixed == 1);
2881
  longlong tmp= (*ref)->val_int_result();
2882
  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;
}


2905 2906
String* Item_ref_null_helper::val_str(String* s)
{
2907
  DBUG_ASSERT(fixed == 1);
2908
  String* tmp= (*ref)->str_result(s);
2909
  owner->was_null|= null_value= (*ref)->null_value;
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  return tmp;
}
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2914
bool Item_ref_null_helper::get_date(TIME *ltime, uint fuzzydate)
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{  
  return (owner->was_null|= null_value= (*ref)->get_date(ltime, fuzzydate));
}
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/*
2921
  Mark item and SELECT_LEXs as dependent if item was resolved in outer SELECT
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  SYNOPSIS
    mark_as_dependent()
2925
    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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*/

2933
static void mark_as_dependent(THD *thd, SELECT_LEX *last, SELECT_LEX *current,
2934
                              Item_ident *resolved_item,
2935
                              Item_ident *mark_item)
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{
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  const char *db_name= (resolved_item->db_name ?
                        resolved_item->db_name : "");
  const char *table_name= (resolved_item->table_name ?
                           resolved_item->table_name : "");
2941
  /* store pointer on SELECT_LEX from which item is dependent */
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  if (mark_item)
    mark_item->depended_from= last;
2944
  current->mark_as_dependent(last);
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  if (thd->lex->describe & DESCRIBE_EXTENDED)
2946 2947 2948
  {
    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] ? "." : ""),
2951
            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;
3051
  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;
  }

3072
  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)
3077
    {
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      cur_field= (Item_ident*) *cur_group->item;
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      cur_match_degree= 0;
      
3081
      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)
    {
3224
      DBUG_ASSERT(*select_ref != 0);
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3225
      if (!select->ref_pointer_array[counter])
3226
      {
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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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3234
    if (group_by_ref)
3235
      return group_by_ref;
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    DBUG_ASSERT(FALSE);
    return NULL; /* So there is no compiler warning. */
3238
  }
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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;
}


3490 3491 3492 3493 3494 3495 3496 3497 3498 3499 3500 3501 3502 3503 3504 3505 3506 3507 3508 3509 3510 3511 3512 3513 3514 3515 3516
/*
  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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3517 3518
            search for a column or derived column named col_ref_i
            [in table T_j] in the FROM clause of Q_k;
3519 3520 3521 3522 3523 3524 3525 3526 3527 3528 3529 3530 3531 3532 3533 3534

            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
*/

3535
bool Item_field::fix_fields(THD *thd, Item **reference)
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3536
{
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3537
  DBUG_ASSERT(fixed == 0);
3538
  if (!field)					// If field is not checked
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3539
  {
3540
    Field *from_field= (Field *)not_found_field;
3541
    bool outer_fixed= false;
3542 3543 3544 3545 3546
    /*
      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,
3550 3551
                                          reference,
                                          IGNORE_EXCEPT_NON_UNIQUE,
3552
                                          !any_privileges,
3553
                                          TRUE)) ==
3554
	not_found_field)
3555
    {
3556
      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);
3565
        if (res != (Item **)not_found_item && (*res)->type() == Item::FIELD_ITEM)
3566 3567 3568
        {
          set_field((*((Item_field**)res))->field);
          return 0;
3569 3570
        }
      }
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      if ((ret= fix_outer_field(thd, &from_field, reference)) < 0)
        goto error;
      else if (!ret)
        return FALSE;
      outer_fixed= TRUE;
3576
    }
3577
    else if (!from_field)
3578
      goto error;
3579

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VIEW  
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3580 3581 3582 3583 3584 3585
    /*
      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
3586
      fix_field'ed during setup_tables()->setup_underlying() (i.e. before
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3587 3588 3589 3590 3591
      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.
    */
3592 3593 3594
    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;
    }

3606
    set_field(from_field);
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    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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  }
3613
  else if (thd->set_query_id && field->query_id != thd->query_id)
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  {
    /* We only come here in unions */
    TABLE *table=field->table;
    field->query_id=thd->query_id;
    table->used_fields++;
3619
    table->used_keys.intersect(field->part_of_key);
3620
  }
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VIEW  
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#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;
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      tab= cached_table->table_name;
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    }
    if (!(have_privileges= (get_column_grant(thd, &field->table->grant,
                                             db, tab, field_name) &
                            VIEW_ANY_ACL)))
    {
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      my_error(ER_COLUMNACCESS_DENIED_ERROR, MYF(0),
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               "ANY", thd->security_ctx->priv_user,
               thd->security_ctx->host_or_ip, field_name, tab);
3642
      goto error;
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    }
  }
#endif
3646
  fixed= 1;
3647
  return FALSE;
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error:
  context->process_error(thd);
  return TRUE;
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}

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


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void Item_field::cleanup()
{
3664
  DBUG_ENTER("Item_field::cleanup");
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  Item_ident::cleanup();
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  /*
    Even if this object was created by direct link to field in setup_wild()
3668
    it will be linked correctly next time by name of field and table alias.
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    I.e. we can drop 'field'.
   */
3671
  field= result_field= 0;
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  DBUG_VOID_RETURN;
3673
}
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/*
  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
*/
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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;
}


/*
3717 3718
  Set a pointer to the multiple equality the field reference belongs to
  (if any)
3719 3720 3721 3722 3723 3724 3725 3726 3727 3728 3729 3730 3731 3732 3733 3734 3735 3736 3737 3738 3739 3740
   
  SYNOPSIS
    equal_fields_propagator()
    arg - reference to list of multiple equalities where
          the field (this object) is to be looked for
  
  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
    of the transform method.  

  RETURN VALUES
    pointer to the replacing constant item, if the field item was substituted 
    pointer to the field item, otherwise.
*/
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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();
  if (!item)
    item= this;
  return item;
}


/*
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  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
*/

Item *Item_field::set_no_const_sub(byte *arg)
{
  if (field->charset() != &my_charset_bin)
    no_const_subst=1;
  return this;
}


/*
3770
  Replace an Item_field for an equal Item_field that evaluated earlier
3771
  (if any)
3772 3773
   
  SYNOPSIS
3774
    replace_equal_field_()
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    arg - a dummy parameter, is not used here
  
  DESCRIPTION
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    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 
3783 3784 3785

  NOTES
    This function is supposed to be called as a callback parameter in calls
3786
    of the thransformer method.  
3787 3788

  RETURN VALUES
3789 3790
    pointer to a replacement Item_field if there is a better equal item;
    this - otherwise.
3791 3792
*/

3793
Item *Item_field::replace_equal_field(byte *arg)
3794 3795 3796 3797
{
  if (item_equal)
  {
    Item_field *subst= item_equal->get_first();
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    if (subst && !field->eq(subst->field))
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      return subst;
3800
  }
3801
  return this;
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}
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3804

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void Item::init_make_field(Send_field *tmp_field,
			   enum enum_field_types field_type)
3807
{
3808
  char *empty_name= (char*) "";
3809
  tmp_field->db_name=		empty_name;
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  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;
3814
  tmp_field->charsetnr=         collation.collation->number;
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  tmp_field->flags=             (maybe_null ? 0 : NOT_NULL_FLAG) | 
                                (my_binary_compare(collation.collation) ?
                                 BINARY_FLAG : 0);
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  tmp_field->type=field_type;
  tmp_field->length=max_length;
  tmp_field->decimals=decimals;
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  if (unsigned_flag)
    tmp_field->flags |= UNSIGNED_FLAG;
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}

3825
void Item::make_field(Send_field *tmp_field)
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{
3827
  init_make_field(tmp_field, field_type());
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}


3831 3832
void Item_empty_string::make_field(Send_field *tmp_field)
{
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  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;
3838
  init_make_field(tmp_field, type);
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}

3841

3842
enum_field_types Item::field_type() const
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{
3844
  switch (result_type()) {
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  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);
3852 3853
    return MYSQL_TYPE_VARCHAR;
  }
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}

3856

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/*
  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)
{
3873 3874
  DBUG_ASSERT(collation.collation);
  if (max_length/collation.collation->mbmaxlen > CONVERT_IF_BIGGER_TO_BLOB)
3875 3876
    return new Field_blob(max_length, maybe_null, name, table,
                          collation.collation);
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  /* Item_type_holder holds the exact type, do not change it */
  if (max_length > 0 &&
      (type() != Item::TYPE_HOLDER || field_type() != MYSQL_TYPE_STRING))
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    return new Field_varstring(max_length, maybe_null, name, table,
                               collation.collation);
  return new Field_string(max_length, maybe_null, name, table,
                          collation.collation);
}


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/*
  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
*/

3898 3899
Field *Item::tmp_table_field_from_field_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 (field_type()) {
3906
  case MYSQL_TYPE_DECIMAL:
3907
  case MYSQL_TYPE_NEWDECIMAL:
3908
    return new Field_new_decimal((char*) 0, max_length, null_ptr, 0,
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                                 Field::NONE, name, table, decimals, 0,
                                 unsigned_flag);
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  case MYSQL_TYPE_TINY:
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    return new Field_tiny((char*) 0, max_length, null_ptr, 0, Field::NONE,
			  name, table, 0, unsigned_flag);
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  case MYSQL_TYPE_SHORT:
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    return new Field_short((char*) 0, max_length, null_ptr, 0, Field::NONE,
			   name, table, 0, unsigned_flag);
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  case MYSQL_TYPE_LONG:
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    return new Field_long((char*) 0, max_length, null_ptr, 0, Field::NONE,
			  name, table, 0, unsigned_flag);
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#ifdef HAVE_LONG_LONG
  case MYSQL_TYPE_LONGLONG:
3922 3923
    return new Field_longlong((char*) 0, max_length, null_ptr, 0, Field::NONE,
			      name, table, 0, unsigned_flag);
3924
#endif
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  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);
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  case MYSQL_TYPE_INT24:
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    return new Field_medium((char*) 0, max_length, null_ptr, 0, Field::NONE,
			    name, table, 0, unsigned_flag);
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  case MYSQL_TYPE_NEWDATE:
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  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:
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    return new Field_timestamp(maybe_null, name, table, &my_charset_bin);
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  case MYSQL_TYPE_DATETIME:
    return new Field_datetime(maybe_null, name, table, &my_charset_bin);
  case MYSQL_TYPE_YEAR:
3947 3948
    return new Field_year((char*) 0, max_length, null_ptr, 0, Field::NONE,
			  name, table);
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  case MYSQL_TYPE_BIT:
3950
    return new Field_bit_as_char(NULL, max_length, null_ptr, 0,
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                                 Field::NONE, name, table);
3952
  default:
3953
    /* This case should never be chosen */
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    DBUG_ASSERT(0);
    /* If something goes awfully wrong, it's better to get a string than die */
3956 3957
  case MYSQL_TYPE_ENUM:
  case MYSQL_TYPE_SET:
3958
  case MYSQL_TYPE_STRING:
3959
  case MYSQL_TYPE_VAR_STRING:
3960
  case MYSQL_TYPE_VARCHAR:
3961
    return make_string_field(table);
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  case MYSQL_TYPE_TINY_BLOB:
  case MYSQL_TYPE_MEDIUM_BLOB:
  case MYSQL_TYPE_LONG_BLOB:
  case MYSQL_TYPE_BLOB:
  case MYSQL_TYPE_GEOMETRY:
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    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,
3972
                          collation.collation);
3973
    break;					// Blob handled outside of case
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  }
}

3977

3978 3979
/* ARGSUSED */
void Item_field::make_field(Send_field *tmp_field)
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{
3981
  field->make_field(tmp_field);
3982
  DBUG_ASSERT(tmp_field->table_name != 0);
3983 3984
  if (name)
    tmp_field->col_name=name;			// Use user supplied name
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}

3987

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3988
/*
3989
  Set a field:s value from a item
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*/

void Item_field::save_org_in_field(Field *to)
{
  if (field->is_null())
  {
    null_value=1;
3997
    set_field_to_null_with_conversions(to, 1);
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  }
  else
  {
    to->set_notnull();
    field_conv(to,field);
    null_value=0;
  }
}

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int Item_field::save_in_field(Field *to, bool no_conversions)
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{
  if (result_field->is_null())
  {
    null_value=1;
4012
    return set_field_to_null_with_conversions(to, no_conversions);
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  }
  else
  {
    to->set_notnull();
    field_conv(to,result_field);
    null_value=0;
  }
  return 0;
}

4023

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/*
  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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int Item_null::save_in_field(Field *field, bool no_conversions)
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4041
{
4042
  return set_field_to_null_with_conversions(field, no_conversions);
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}


4046 4047 4048 4049 4050 4051 4052 4053
/*
  Store null in field

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

  RETURN VALUES
4054
    0	 OK
4055 4056 4057
    1	 Field doesn't support NULL values
*/   

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int Item_null::save_safe_in_field(Field *field)
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{
  return set_field_to_null(field);
}


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int Item::save_in_field(Field *field, bool no_conversions)
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{
4066
  int error;
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  if (result_type() == STRING_RESULT ||
      result_type() == REAL_RESULT &&
      field->result_type() == STRING_RESULT)
  {
    String *result;
4072
    CHARSET_INFO *cs= collation.collation;
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    char buff[MAX_FIELD_WIDTH];		// Alloc buffer for small columns
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    str_value.set_quick(buff, sizeof(buff), cs);
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    result=val_str(&str_value);
    if (null_value)
4077
    {
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      str_value.set_quick(0, 0, cs);
4079
      return set_field_to_null_with_conversions(field, no_conversions);
4080
    }
4081 4082 4083

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

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    field->set_notnull();
4085
    error=field->store(result->ptr(),result->length(),cs);
4086
    str_value.set_quick(0, 0, cs);
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  }
  else if (result_type() == REAL_RESULT)
  {
4090
    double nr= val_real();
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    if (null_value)
      return set_field_to_null(field);
    field->set_notnull();
4094
    error=field->store(nr);
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  }
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  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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  else
  {
    longlong nr=val_int();
    if (null_value)
4109
      return set_field_to_null_with_conversions(field, no_conversions);
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    field->set_notnull();
4111
    error=field->store(nr, unsigned_flag);
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  }
4113
  return error;
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}

4116

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int Item_string::save_in_field(Field *field, bool no_conversions)
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{
  String *result;
  result=val_str(&str_value);
  if (null_value)
    return set_field_to_null(field);
  field->set_notnull();
4124
  return field->store(result->ptr(),result->length(),collation.collation);
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}

4127

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4128
int Item_uint::save_in_field(Field *field, bool no_conversions)
4129
{
4130
  /* Item_int::save_in_field handles both signed and unsigned. */
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4131
  return Item_int::save_in_field(field, no_conversions);
4132 4133
}

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int Item_int::save_in_field(Field *field, bool no_conversions)
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{
  longlong nr=val_int();
  if (null_value)
    return set_field_to_null(field);
  field->set_notnull();
4141
  return field->store(nr, unsigned_flag);
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}

4144 4145 4146 4147 4148 4149 4150 4151

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


4152 4153 4154 4155 4156 4157 4158 4159 4160 4161 4162 4163 4164 4165 4166 4167
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;
}


4168 4169
Item *Item_int_with_ref::new_item()
{
4170
  DBUG_ASSERT(ref->const_item());
4171 4172 4173 4174 4175 4176 4177 4178 4179 4180
  /*
    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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Item_num *Item_uint::neg()
{
4183
  Item_decimal *item= new Item_decimal(value, 1);
4184
  return item->neg();
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}
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4186

4187

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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);
}


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

4216
Item_float::Item_float(const char *str_arg, uint length)
4217 4218
{
  int error;
4219 4220 4221
  char *end_not_used;
  value= my_strntod(&my_charset_bin, (char*) str_arg, length, &end_not_used,
                    &error);
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  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);
4229
    my_error(ER_ILLEGAL_VALUE_FOR_TYPE, MYF(0), "double", (char*) str_arg);
4230 4231
  }
  presentation= name=(char*) str_arg;
4232
  decimals=(uint8) nr_of_decimals(str_arg, str_arg+length);
4233 4234 4235 4236 4237
  max_length=length;
  fixed= 1;
}


4238
int Item_float::save_in_field(Field *field, bool no_conversions)
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bk@work.mysql.com committed
4239
{
4240
  double nr= val_real();
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4241 4242 4243
  if (null_value)
    return set_field_to_null(field);
  field->set_notnull();
4244
  return field->store(nr);
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4245 4246
}

4247

4248
void Item_float::print(String *str)
4249 4250 4251 4252 4253 4254 4255 4256 4257 4258 4259 4260 4261
{
  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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4262 4263 4264 4265 4266
/*
  hex item
  In string context this is a binary string.
  In number context this is a longlong value.
*/
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4267

4268
bool Item_float::eq(const Item *arg, bool binary_cmp) const
4269 4270 4271 4272 4273 4274 4275 4276
{
  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;
4277
    return item->val_real() == value;
4278 4279 4280 4281
  }
  return FALSE;
}

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4282

4283
inline uint char_val(char X)
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4284 4285 4286 4287 4288 4289
{
  return (uint) (X >= '0' && X <= '9' ? X-'0' :
		 X >= 'A' && X <= 'Z' ? X-'A'+10 :
		 X-'a'+10);
}

4290

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4291
Item_hex_string::Item_hex_string(const char *str, uint str_length)
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4292 4293 4294 4295 4296 4297
{
  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;
4298
  str_value.set(ptr,max_length,&my_charset_bin);
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4299 4300 4301 4302 4303 4304 4305 4306 4307
  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
4308
  collation.set(&my_charset_bin, DERIVATION_COERCIBLE);
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4309
  fixed= 1;
4310
  unsigned_flag= 1;
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4311 4312
}

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4313
longlong Item_hex_string::val_int()
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4314
{
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4315
  // following assert is redundant, because fixed=1 assigned in constructor
4316
  DBUG_ASSERT(fixed == 1);
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4317 4318 4319 4320 4321 4322 4323 4324 4325 4326
  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;
}


4327 4328 4329 4330 4331 4332 4333 4334 4335 4336
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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4337
int Item_hex_string::save_in_field(Field *field, bool no_conversions)
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4338
{
4339
  int error;
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4340 4341 4342
  field->set_notnull();
  if (field->result_type() == STRING_RESULT)
  {
4343
    error=field->store(str_value.ptr(),str_value.length(),collation.collation);
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4344 4345 4346 4347
  }
  else
  {
    longlong nr=val_int();
4348
    error=field->store(nr, TRUE);    // Assume hex numbers are unsigned
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4349
  }
4350
  return error;
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4351 4352 4353
}


4354
bool Item_hex_string::eq(const Item *arg, bool binary_cmp) const
4355 4356 4357 4358 4359 4360 4361 4362 4363 4364
{
  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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4365

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4366
Item *Item_hex_string::safe_charset_converter(CHARSET_INFO *tocs)
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4367 4368 4369 4370 4371 4372 4373
{
  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();
4374
  conv->str_value.mark_as_const();
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4375 4376 4377 4378
  return conv;
}


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4379 4380 4381 4382 4383 4384 4385 4386 4387 4388 4389 4390 4391 4392 4393 4394 4395 4396 4397 4398 4399 4400 4401 4402 4403 4404 4405 4406 4407 4408 4409 4410 4411 4412 4413 4414 4415 4416
/*
  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;
}


4417 4418 4419 4420 4421
/*
  Pack data in buffer for sending
*/

bool Item_null::send(Protocol *protocol, String *packet)
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4422
{
4423
  return protocol->store_null();
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4424 4425 4426
}

/*
4427
  This is only called from items that is not of type item_field
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4428 4429
*/

4430
bool Item::send(Protocol *protocol, String *buffer)
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4431
{
4432 4433
  bool result;
  enum_field_types type;
4434
  LINT_INIT(result);                     // Will be set if null_value == 0
4435 4436 4437

  switch ((type=field_type())) {
  default:
4438 4439 4440 4441 4442 4443 4444 4445 4446
  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:
4447 4448
  case MYSQL_TYPE_STRING:
  case MYSQL_TYPE_VAR_STRING:
4449
  case MYSQL_TYPE_VARCHAR:
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4450
  case MYSQL_TYPE_BIT:
4451
  case MYSQL_TYPE_NEWDECIMAL:
4452 4453 4454
  {
    String *res;
    if ((res=val_str(buffer)))
4455
      result= protocol->store(res->ptr(),res->length(),res->charset());
4456 4457 4458 4459 4460 4461 4462 4463 4464 4465 4466
    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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4467
  case MYSQL_TYPE_YEAR:
4468 4469 4470 4471 4472 4473 4474
  {
    longlong nr;
    nr= val_int();
    if (!null_value)
      result= protocol->store_short(nr);
    break;
  }
4475
  case MYSQL_TYPE_INT24:
4476 4477 4478 4479 4480 4481 4482 4483 4484 4485 4486 4487 4488 4489 4490 4491
  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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4492 4493 4494
  case MYSQL_TYPE_FLOAT:
  {
    float nr;
4495
    nr= (float) val_real();
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4496 4497 4498 4499
    if (!null_value)
      result= protocol->store(nr, decimals, buffer);
    break;
  }
4500 4501
  case MYSQL_TYPE_DOUBLE:
  {
4502
    double nr= val_real();
4503 4504 4505 4506 4507 4508
    if (!null_value)
      result= protocol->store(nr, decimals, buffer);
    break;
  }
  case MYSQL_TYPE_DATETIME:
  case MYSQL_TYPE_DATE:
4509
  case MYSQL_TYPE_TIMESTAMP:
4510 4511
  {
    TIME tm;
4512
    get_date(&tm, TIME_FUZZY_DATE);
4513 4514 4515 4516 4517 4518 4519 4520 4521 4522 4523 4524 4525 4526 4527 4528 4529 4530 4531 4532 4533
    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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4534 4535
}

4536 4537

bool Item_field::send(Protocol *protocol, String *buffer)
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4538
{
4539
  return protocol->store(result_field);
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4540 4541
}

4542

4543 4544 4545 4546 4547
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)
4548 4549 4550 4551
{
  /*
    This constructor used to create some internals references over fixed items
  */
4552
  DBUG_ASSERT(ref != 0);
4553
  if (*ref && (*ref)->fixed)
4554 4555 4556 4557
    set_properties();
}


4558
/*
4559
  Resolve the name of a reference to a column reference.
4560 4561 4562

  SYNOPSIS
    Item_ref::fix_fields()
4563 4564
    thd       [in]      current thread
    reference [in/out]  view column if this item was resolved to a view column
4565 4566

  DESCRIPTION
4567 4568
    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
4569 4570
    used typically for columns in the HAVING clause which are not under
    aggregate functions.
4571 4572

  NOTES
4573 4574
    The name resolution algorithm used is (where [T_j] is an optional table
    name that qualifies the column name):
4575

4576 4577 4578
      resolve_extended([T_j].col_ref_i)
      {
        Search for a column or derived column named col_ref_i [in table T_j]
4579
        in the SELECT and GROUP clauses of Q.
4580

4581 4582
        if such a column is NOT found AND    // Lookup in outer queries.
           there are outer queries
4583 4584 4585
        {
          for each outer query Q_k beginning from the inner-most one
         {
4586 4587 4588 4589 4590 4591 4592 4593
            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
4594 4595 4596 4597 4598 4599 4600
            {
              search for a column or derived column named col_ref_i
              [in table T_j] in the FROM clause of Q_k;
            }
          }
        }
      }
4601 4602

    This procedure treats GROUP BY and SELECT clauses as one namespace for
4603 4604 4605
    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.
4606

4607 4608 4609
  POSTCONDITION
    Item_ref::ref is 0 or points to a valid item

4610 4611 4612 4613
  RETURN
    TRUE  if error
    FALSE on success
*/
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4614

4615
bool Item_ref::fix_fields(THD *thd, Item **reference)
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bk@work.mysql.com committed
4616
{
4617
  enum_parsing_place place= NO_MATTER;
4618
  DBUG_ASSERT(fixed == 0);
4619 4620
  SELECT_LEX *current_sel= thd->lex->current_select;

4621
  if (!ref || ref == not_found_item)
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4622
  {
4623 4624 4625
    if (!(ref= resolve_ref_in_select_and_group(thd, this,
                                               context->select_lex)))
      goto error;             /* Some error occurred (e.g. ambiguous names). */
4626

4627
    if (ref == not_found_item) /* This reference was not resolved. */
4628
    {
4629 4630
      Name_resolution_context *last_checked_context= context;
      Name_resolution_context *outer_context= context->outer_context;
4631 4632 4633
      Field *from_field;
      ref= 0;

4634
      if (!outer_context)
4635 4636 4637 4638
      {
        /* The current reference cannot be resolved in this query. */
        my_error(ER_BAD_FIELD_ERROR,MYF(0),
                 this->full_name(), current_thd->where);
4639
        goto error;
4640
      }
4641

4642
      /*
4643 4644 4645
        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).
4646

4647 4648 4649
        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.
4650
      */
4651 4652
      from_field= (Field*) not_found_field;

4653
      do
4654
      {
4655 4656 4657 4658
        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;
4659

4660
        /* Search in the SELECT and GROUP lists of the outer select. */
4661
        if (outer_context->resolve_in_select_list)
4662
        {
4663 4664
          if (!(ref= resolve_ref_in_select_and_group(thd, this, select)))
            goto error; /* Some error occurred (e.g. ambiguous names). */
4665
          if (ref != not_found_item)
4666
          {
4667 4668 4669 4670
            DBUG_ASSERT(*ref && (*ref)->fixed);
            prev_subselect_item->used_tables_cache|= (*ref)->used_tables();
            prev_subselect_item->const_item_cache&= (*ref)->const_item();
            break;
4671 4672
          }
          /*
4673 4674 4675
            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.
4676
          */
4677
          ref= 0;
4678
        }
4679

4680 4681 4682 4683 4684
        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).
4685
          TODO:
4686 4687 4688 4689 4690 4691
          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 ||
4692 4693
             (!select->with_sum_func &&
              select->group_list.elements == 0)))
4694
        {
4695
          /*
4696 4697 4698
            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
4699
          */
4700
          from_field= find_field_in_tables(thd, this,
4701 4702 4703 4704
                                           outer_context->
                                             first_name_resolution_table,
                                           outer_context->
                                             last_name_resolution_table,
4705 4706
                                           reference,
                                           IGNORE_EXCEPT_NON_UNIQUE,
4707
                                           TRUE, TRUE);
4708
          if (! from_field)
4709
            goto error;
4710
          if (from_field == view_ref_found)
4711
          {
4712 4713 4714 4715 4716 4717
            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);
4718 4719
            mark_as_dependent(thd, last_checked_context->select_lex,
                              context->select_lex, this,
4720 4721 4722 4723 4724 4725 4726
                              ((type == REF_ITEM || type == FIELD_ITEM) ?
                               (Item_ident*) (*reference) :
                               0));
            /*
              view reference found, we substituted it instead of this
              Item, so can quit
            */
4727 4728
            return FALSE;
          }
4729 4730
          if (from_field != not_found_field)
          {
4731 4732 4733 4734 4735 4736 4737 4738 4739 4740 4741 4742 4743 4744 4745 4746 4747 4748 4749
            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);
            }
4750 4751 4752 4753
            prev_subselect_item->used_tables_cache|= from_field->table->map;
            prev_subselect_item->const_item_cache= 0;
            break;
          }
4754
        }
4755 4756 4757 4758 4759 4760
        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;

4761 4762
        outer_context= outer_context->outer_context;
      } while (outer_context);
4763 4764 4765

      DBUG_ASSERT(from_field != 0 && from_field != view_ref_found);
      if (from_field != not_found_field)
4766
      {
4767 4768
        Item_field* fld;
        if (!(fld= new Item_field(from_field)))
4769
          goto error;
4770
        thd->change_item_tree(reference, fld);
4771 4772
        mark_as_dependent(thd, last_checked_context->select_lex,
                          thd->lex->current_select, this, fld);
4773 4774 4775 4776 4777 4778
        return FALSE;
      }
      if (ref == 0)
      {
        /* The item was not a table field and not a reference */
        my_error(ER_BAD_FIELD_ERROR, MYF(0),
4779
                 this->full_name(), current_thd->where);
4780
        goto error;
4781
      }
4782 4783
      /* Should be checked in resolve_ref_in_select_and_group(). */
      DBUG_ASSERT(*ref && (*ref)->fixed);
4784 4785
      mark_as_dependent(thd, last_checked_context->select_lex,
                        context->select_lex, this, this);
4786
    }
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bk@work.mysql.com committed
4787
  }
4788

4789
  DBUG_ASSERT(*ref);
4790
  /*
4791 4792 4793
    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.
4794
  */
4795
  if (((*ref)->with_sum_func && name &&
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igor@rurik.mysql.com committed
4796 4797
       !(current_sel->linkage != GLOBAL_OPTIONS_TYPE &&
         current_sel->having_fix_field)) ||
4798 4799
      !(*ref)->fixed)
  {
4800 4801 4802 4803
    my_error(ER_ILLEGAL_REFERENCE, MYF(0),
             name, ((*ref)->with_sum_func?
                    "reference to group function":
                    "forward reference in item list"));
4804
    goto error;
4805
  }
4806 4807 4808

  set_properties();

4809
  if ((*ref)->check_cols(1))
4810
    goto error;
4811
  return FALSE;
4812 4813 4814 4815

error:
  context->process_error(thd);
  return TRUE;
4816 4817
}

4818

4819 4820
void Item_ref::set_properties()
{
4821 4822 4823
  max_length= (*ref)->max_length;
  maybe_null= (*ref)->maybe_null;
  decimals=   (*ref)->decimals;
4824
  collation.set((*ref)->collation);
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monty@mysql.com committed
4825 4826 4827 4828
  /*
    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
4829
  with_sum_func= (*ref)->with_sum_func;
timour@mysql.com's avatar
Merge  
timour@mysql.com committed
4830
  unsigned_flag= (*ref)->unsigned_flag;
4831 4832 4833 4834
  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
4835
  fixed= 1;
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bk@work.mysql.com committed
4836 4837
}

4838

hf@deer.(none)'s avatar
hf@deer.(none) committed
4839 4840
void Item_ref::cleanup()
{
4841
  DBUG_ENTER("Item_ref::cleanup");
hf@deer.(none)'s avatar
hf@deer.(none) committed
4842
  Item_ident::cleanup();
4843
  result_field= 0;
4844
  DBUG_VOID_RETURN;
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hf@deer.(none) committed
4845 4846 4847
}


4848 4849
void Item_ref::print(String *str)
{
4850
  if (ref)
igor@rurik.mysql.com's avatar
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4851 4852 4853 4854 4855 4856 4857 4858 4859 4860
  {
    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);
  }
4861 4862 4863 4864 4865
  else
    Item_ident::print(str);
}


4866 4867 4868 4869 4870 4871 4872 4873
bool Item_ref::send(Protocol *prot, String *tmp)
{
  if (result_field)
    return prot->store(result_field);
  return (*ref)->send(prot, tmp);
}


4874 4875 4876 4877 4878 4879 4880 4881
double Item_ref::val_result()
{
  if (result_field)
  {
    if ((null_value= result_field->is_null()))
      return 0.0;
    return result_field->val_real();
  }
4882
  return val_real();
4883 4884 4885 4886 4887 4888 4889 4890
}


longlong Item_ref::val_int_result()
{
  if (result_field)
  {
    if ((null_value= result_field->is_null()))
4891
      return 0;
4892 4893 4894 4895 4896 4897 4898 4899 4900 4901 4902 4903 4904 4905 4906 4907 4908 4909 4910
    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);
}


4911 4912 4913 4914 4915 4916 4917 4918 4919 4920 4921 4922 4923 4924 4925 4926 4927 4928
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;
4929
    switch (result_field->result_type()) {
4930
    case INT_RESULT:
4931
      return result_field->val_int() != 0;
4932
    case DECIMAL_RESULT:
4933 4934 4935 4936 4937 4938 4939
    {
      my_decimal decimal_value;
      my_decimal *val= result_field->val_decimal(&decimal_value);
      if (val)
        return !my_decimal_is_zero(val);
      return 0;
    }
4940 4941 4942 4943 4944 4945 4946 4947 4948 4949 4950 4951 4952 4953 4954 4955 4956 4957 4958 4959 4960 4961 4962 4963 4964 4965 4966 4967 4968 4969 4970 4971 4972 4973 4974 4975 4976 4977 4978 4979 4980 4981 4982 4983 4984 4985 4986 4987 4988 4989 4990
    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);
4991
  return (*ref)->is_null();
4992 4993 4994 4995 4996 4997 4998 4999 5000 5001 5002
}


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
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5003
  my_decimal *val= (*ref)->val_decimal_result(decimal_value);
5004 5005 5006 5007
  null_value= (*ref)->null_value;
  return val;
}

5008 5009 5010
int Item_ref::save_in_field(Field *to, bool no_conversions)
{
  int res;
5011 5012
  if (result_field)
  {
5013 5014 5015 5016 5017
    if (result_field->is_null())
    {
      null_value= 1;
      return set_field_to_null_with_conversions(to, no_conversions);
    }
5018 5019 5020
    to->set_notnull();
    field_conv(to, result_field);
    null_value= 0;
5021 5022 5023 5024 5025 5026 5027
    return 0;
  }
  res= (*ref)->save_in_field(to, no_conversions);
  null_value= (*ref)->null_value;
  return res;
}

5028

5029 5030 5031 5032 5033 5034
void Item_ref::save_org_in_field(Field *field)
{
  (*ref)->save_org_in_field(field);
}


5035 5036 5037 5038 5039 5040 5041 5042 5043 5044
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;
5045
}
5046 5047


5048 5049
void Item_ref_null_helper::print(String *str)
{
5050
  str->append(STRING_WITH_LEN("<ref_null_helper>("));
5051
  if (ref)
5052 5053 5054 5055 5056 5057 5058
    (*ref)->print(str);
  else
    str->append('?');
  str->append(')');
}


5059 5060 5061 5062 5063 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
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
5101
  return (*ref)->is_null();
5102 5103 5104 5105 5106 5107 5108 5109 5110
}


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


5111 5112 5113 5114 5115 5116 5117 5118 5119 5120 5121 5122 5123 5124 5125 5126 5127 5128 5129 5130 5131 5132 5133 5134
/*
  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);
}

5135
/*
5136
  Compare two view column references for equality.
5137 5138 5139 5140 5141 5142 5143

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

  DESCRIPTION
5144 5145
    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
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5146 5147
    references resolve to the same item. It is assumed that both
    items are of the same type.
5148 5149 5150 5151 5152 5153 5154 5155 5156

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


bool Item_direct_view_ref::eq(const Item *item, bool binary_cmp) const
{
5157 5158 5159 5160 5161 5162
  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
5163 5164
      DBUG_ASSERT((*ref)->real_item()->type() == 
                  item_ref_ref->real_item()->type());
5165
      return ((*ref)->real_item() == item_ref_ref->real_item());
5166 5167 5168
    }
  }
  return FALSE;
5169
}
5170

hf@deer.mysql.r18.ru's avatar
SCRUM  
hf@deer.mysql.r18.ru committed
5171 5172
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
5173
  return item->type() == DEFAULT_VALUE_ITEM && 
hf@deer.mysql.r18.ru's avatar
SCRUM  
hf@deer.mysql.r18.ru committed
5174 5175 5176
    ((Item_default_value *)item)->arg->eq(arg, binary_cmp);
}

5177

5178
bool Item_default_value::fix_fields(THD *thd, Item **items)
hf@deer.mysql.r18.ru's avatar
SCRUM  
hf@deer.mysql.r18.ru committed
5179
{
5180
  Item *real_arg;
5181 5182
  Item_field *field_arg;
  Field *def_field;
5183
  DBUG_ASSERT(fixed == 0);
5184

hf@deer.mysql.r18.ru's avatar
SCRUM  
hf@deer.mysql.r18.ru committed
5185
  if (!arg)
5186 5187
  {
    fixed= 1;
5188
    return FALSE;
5189
  }
5190 5191 5192
  if (!arg->fixed && arg->fix_fields(thd, &arg))
    goto error;

5193

5194 5195
  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
5196
  {
5197
    my_error(ER_NO_DEFAULT_FOR_FIELD, MYF(0), arg->name);
5198
    goto error;
hf@deer.mysql.r18.ru's avatar
SCRUM  
hf@deer.mysql.r18.ru committed
5199
  }
5200

5201
  field_arg= (Item_field *)real_arg;
5202 5203
  if (field_arg->field->flags & NO_DEFAULT_VALUE_FLAG)
  {
5204
    my_error(ER_NO_DEFAULT_FOR_FIELD, MYF(0), field_arg->field->field_name);
5205
    goto error;
5206 5207
  }
  if (!(def_field= (Field*) sql_alloc(field_arg->field->size_of())))
5208
    goto error;
hf@deer.mysql.r18.ru's avatar
SCRUM  
hf@deer.mysql.r18.ru committed
5209
  memcpy(def_field, field_arg->field, field_arg->field->size_of());
5210
  def_field->move_field(def_field->table->s->default_values -
5211
                        def_field->table->record[0]);
hf@deer.mysql.r18.ru's avatar
SCRUM  
hf@deer.mysql.r18.ru committed
5212
  set_field(def_field);
5213
  return FALSE;
5214 5215 5216 5217

error:
  context->process_error(thd);
  return TRUE;
hf@deer.mysql.r18.ru's avatar
SCRUM  
hf@deer.mysql.r18.ru committed
5218 5219
}

5220

hf@deer.mysql.r18.ru's avatar
SCRUM  
hf@deer.mysql.r18.ru committed
5221 5222
void Item_default_value::print(String *str)
{
hf@deer.mysql.r18.ru's avatar
SCRUM  
hf@deer.mysql.r18.ru committed
5223 5224
  if (!arg)
  {
5225
    str->append(STRING_WITH_LEN("default"));
hf@deer.mysql.r18.ru's avatar
SCRUM  
hf@deer.mysql.r18.ru committed
5226
    return;
hf@deer.mysql.r18.ru's avatar
SCRUM  
hf@deer.mysql.r18.ru committed
5227
  }
5228
  str->append(STRING_WITH_LEN("default("));
hf@deer.mysql.r18.ru's avatar
SCRUM  
hf@deer.mysql.r18.ru committed
5229 5230 5231
  arg->print(str);
  str->append(')');
}
5232

5233 5234 5235 5236 5237 5238 5239

int Item_default_value::save_in_field(Field *field_arg, bool no_conversions)
{
  if (!arg)
  {
    if (field_arg->flags & NO_DEFAULT_VALUE_FLAG)
    {
5240 5241
      if (context->error_processor == &view_error_processor)
      {
bell@sanja.is.com.ua's avatar
bell@sanja.is.com.ua committed
5242
        TABLE_LIST *view= cached_table->top_table();
5243 5244 5245 5246 5247 5248 5249 5250 5251 5252 5253 5254 5255 5256 5257
        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);
      }
5258 5259 5260 5261 5262 5263 5264 5265 5266
      return 1;
    }
    field_arg->set_default();
    return 0;
  }
  return Item_field::save_in_field(field_arg, no_conversions);
}


5267 5268 5269 5270 5271 5272 5273
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);
}


5274
bool Item_insert_value::fix_fields(THD *thd, Item **items)
5275
{
5276
  DBUG_ASSERT(fixed == 0);
5277
  /* We should only check that arg is in first table */
5278
  if (!arg->fixed)
5279
  {
5280 5281 5282 5283
    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);
5284
    context->last_name_resolution_table= orig_next_table;
5285 5286
    if (res)
      return TRUE;
5287
  }
5288

5289 5290 5291 5292 5293
  if (arg->type() == REF_ITEM)
  {
    Item_ref *ref= (Item_ref *)arg;
    if (ref->ref[0]->type() != FIELD_ITEM)
    {
5294
      my_error(ER_BAD_FIELD_ERROR, MYF(0), "", "VALUES() function");
5295
      return TRUE;
5296 5297 5298
    }
    arg= ref->ref[0];
  }
5299 5300 5301 5302 5303 5304
  /*
    According to our SQL grammar, VALUES() function can reference
    only to a column.
  */
  DBUG_ASSERT(arg->type() == FIELD_ITEM);

5305
  Item_field *field_arg= (Item_field *)arg;
5306

5307 5308 5309 5310
  if (field_arg->field->table->insert_values)
  {
    Field *def_field= (Field*) sql_alloc(field_arg->field->size_of());
    if (!def_field)
5311
      return TRUE;
5312 5313 5314 5315 5316 5317 5318
    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
  {
5319
    Field *tmp_field= field_arg->field;
5320
    /* charset doesn't matter here, it's to avoid sigsegv only */
5321 5322
    set_field(new Field_null(0, 0, Field::NONE, tmp_field->field_name,
			     tmp_field->table, &my_charset_bin));
5323
  }
5324
  return FALSE;
5325 5326 5327 5328
}

void Item_insert_value::print(String *str)
{
5329
  str->append(STRING_WITH_LEN("values("));
5330 5331 5332 5333
  arg->print(str);
  str->append(')');
}

5334 5335

/*
5336 5337
  Find index of Field object which will be appropriate for item
  representing field of row being changed in trigger.
5338 5339 5340 5341 5342

  SYNOPSIS
    setup_field()
      thd   - current thread context
      table - table of trigger (and where we looking for fields)
5343
      table_grant_info - GRANT_INFO of the subject table
5344 5345 5346

  NOTE
    This function does almost the same as fix_fields() for Item_field
5347 5348 5349 5350 5351 5352 5353 5354
    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.
5355
*/
5356

5357 5358
void Item_trigger_field::setup_field(THD *thd, TABLE *table,
                                     GRANT_INFO *table_grant_info)
5359 5360 5361 5362 5363
{
  bool save_set_query_id= thd->set_query_id;

  /* TODO: Think more about consequences of this step. */
  thd->set_query_id= 0;
5364 5365 5366 5367
  /*
    Try to find field by its name and if it will be found
    set field_idx properly.
  */
5368
  (void)find_field_in_table(thd, table, field_name, (uint) strlen(field_name),
5369
                            0, &field_idx);
5370
  thd->set_query_id= save_set_query_id;
5371
  triggers= table->triggers;
5372
  table_grants= table_grant_info;
5373 5374 5375 5376 5377 5378 5379 5380 5381 5382 5383 5384
}


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);
}


5385
void Item_trigger_field::set_required_privilege(bool rw)
5386 5387 5388 5389 5390 5391 5392 5393 5394
{
  /*
    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);
}


5395
bool Item_trigger_field::set_value(THD *thd, sp_rcontext */*ctx*/, Item **it)
5396
{
5397
  Item *item= sp_prepare_func_item(thd, it);
5398 5399 5400 5401 5402 5403

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


5404
bool Item_trigger_field::fix_fields(THD *thd, Item **items)
5405 5406 5407 5408 5409 5410
{
  /*
    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. :)
  */
5411

5412
  DBUG_ASSERT(fixed == 0);
5413

5414 5415
  /* Set field. */

5416
  if (field_idx != (uint)-1)
5417
  {
5418 5419 5420 5421 5422 5423 5424 5425
#ifndef NO_EMBEDDED_ACCESS_CHECKS
    /*
      Check access privileges for the subject table. We check privileges only
      in runtime.
    */

    if (table_grants)
    {
5426
      table_grants->want_privilege= want_privilege;
5427 5428 5429 5430 5431 5432 5433 5434

      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

5435 5436
    field= (row_version == OLD_ROW) ? triggers->old_field[field_idx] :
                                      triggers->new_field[field_idx];
5437 5438
    set_field(field);
    fixed= 1;
5439
    return FALSE;
5440 5441 5442 5443
  }

  my_error(ER_BAD_FIELD_ERROR, MYF(0), field_name,
           (row_version == NEW_ROW) ? "NEW" : "OLD");
5444
  return TRUE;
5445 5446 5447 5448 5449 5450 5451 5452 5453 5454 5455 5456 5457
}


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()
{
5458
  want_privilege= original_privilege;
5459 5460 5461 5462 5463 5464 5465 5466
  /*
    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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5467
/*
5468 5469
  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;
5476
  if (a == INT_RESULT && b == INT_RESULT)
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5477
    return INT_RESULT;
5478 5479
  else if (a == ROW_RESULT || b == ROW_RESULT)
    return ROW_RESULT;
5480 5481 5482
  if ((a == INT_RESULT || a == DECIMAL_RESULT) &&
      (b == INT_RESULT || b == DECIMAL_RESULT))
    return DECIMAL_RESULT;
5483
  return REAL_RESULT;
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5484 5485 5486
}


5487
void resolve_const_item(THD *thd, Item **ref, Item *comp_item)
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5488
{
5489
  Item *item= *ref;
5490
  Item *new_item= NULL;
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  if (item->basic_const_item())
5492
    return;                                     // Can't be better
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5493 5494 5495 5496
  Item_result res_type=item_cmp_type(comp_item->result_type(),
				     item->result_type());
  char *name=item->name;			// Alloced by sql_alloc

5497
  switch (res_type) {
5498
  case STRING_RESULT:
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5499 5500
  {
    char buff[MAX_FIELD_WIDTH];
5501
    String tmp(buff,sizeof(buff),&my_charset_bin),*result;
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5502 5503
    result=item->val_str(&tmp);
    if (item->null_value)
5504 5505 5506 5507 5508 5509 5510
      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());
    }
5511
    break;
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5512
  }
5513
  case INT_RESULT:
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  {
    longlong result=item->val_int();
    uint length=item->max_length;
    bool null_value=item->null_value;
5518 5519
    new_item= (null_value ? (Item*) new Item_null(name) :
               (Item*) new Item_int(name, result, length));
5520
    break;
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5521
  }
5522
  case ROW_RESULT:
5523
  if (item->type() == Item::ROW_ITEM && comp_item->type() == Item::ROW_ITEM)
5524
  {
5525 5526 5527 5528 5529 5530 5531 5532
    /*
      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);
    */
5533 5534 5535
    Item_row *item_row= (Item_row*) item;
    Item_row *comp_item_row= (Item_row*) comp_item;
    uint col;
5536 5537 5538
    new_item= 0;
    /*
      If item and comp_item are both Item_rows and have same number of cols
5539 5540 5541
      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.
5542
    */
5543 5544 5545 5546 5547
    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));
5548
    break;
5549
  }
5550
  /* Fallthrough */
5551
  case REAL_RESULT:
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5552
  {						// It must REAL_RESULT
5553
    double result= item->val_real();
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5554 5555
    uint length=item->max_length,decimals=item->decimals;
    bool null_value=item->null_value;
5556
    new_item= (null_value ? (Item*) new Item_null(name) : (Item*)
5557 5558 5559 5560 5561 5562 5563 5564 5565 5566 5567 5568 5569 5570 5571 5572
               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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5573
  }
5574 5575
  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];
5593 5594
    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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5595 5596 5597
    item_result=item->val_str(&item_tmp);
    if (item->null_value)
      return 1;					// This must be true
5598
    field->val_str(&field_tmp);
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5599
    return !stringcmp(&field_tmp,item_result);
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5600 5601 5602
  }
  if (res_type == INT_RESULT)
    return 1;					// Both where of type int
5603 5604 5605 5606 5607 5608 5609 5610 5611 5612
  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);
  }
5613
  double result= item->val_real();
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5614 5615 5616 5617 5618
  if (item->null_value)
    return 1;
  return result == field->val_real();
}

5619 5620
Item_cache* Item_cache::get_cache(Item_result type)
{
5621
  switch (type) {
5622 5623 5624 5625
  case INT_RESULT:
    return new Item_cache_int();
  case REAL_RESULT:
    return new Item_cache_real();
5626 5627
  case DECIMAL_RESULT:
    return new Item_cache_decimal();
5628 5629
  case STRING_RESULT:
    return new Item_cache_str();
5630 5631
  case ROW_RESULT:
    return new Item_cache_row();
5632 5633 5634 5635 5636 5637 5638
  default:
    // should never be in real life
    DBUG_ASSERT(0);
    return 0;
  }
}

5639 5640 5641

void Item_cache::print(String *str)
{
5642
  str->append(STRING_WITH_LEN("<cache>("));
5643 5644 5645 5646 5647 5648 5649 5650 5651 5652 5653 5654
  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;
5655 5656 5657 5658 5659 5660 5661 5662 5663 5664 5665 5666 5667 5668 5669 5670 5671
  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;
5672 5673 5674 5675 5676 5677 5678 5679 5680 5681
}


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


5682 5683 5684
longlong Item_cache_real::val_int()
{
  DBUG_ASSERT(fixed == 1);
5685
  return (longlong) rint(value);
5686 5687 5688 5689 5690 5691 5692 5693 5694 5695 5696 5697 5698 5699 5700 5701 5702 5703 5704 5705 5706 5707
}


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);
5708
  if (!(null_value= item->null_value) && val != &decimal_value)
5709 5710 5711 5712 5713 5714 5715 5716 5717 5718 5719 5720 5721 5722 5723 5724 5725 5726 5727 5728 5729 5730 5731 5732 5733 5734 5735 5736 5737 5738 5739 5740 5741 5742 5743
    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;
}


5744 5745
void Item_cache_str::store(Item *item)
{
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merge  
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5746
  value_buff.set(buffer, sizeof(buffer), item->collation.collation);
5747
  value= item->str_result(&value_buff);
5748 5749
  if ((null_value= item->null_value))
    value= 0;
5750
  else if (value != &value_buff)
5751 5752 5753 5754 5755 5756 5757 5758 5759
  {
    /*
      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;
    */
5760 5761
    value_buff.copy(*value);
    value= &value_buff;
5762 5763
  }
}
5764

5765
double Item_cache_str::val_real()
5766 5767
{
  DBUG_ASSERT(fixed == 1);
5768 5769
  int err_not_used;
  char *end_not_used;
5770
  if (value)
5771
    return my_strntod(value->charset(), (char*) value->ptr(),
5772 5773
		      value->length(), &end_not_used, &err_not_used);
  return (double) 0;
5774
}
5775 5776


5777 5778
longlong Item_cache_str::val_int()
{
5779
  DBUG_ASSERT(fixed == 1);
5780
  int err;
5781 5782
  if (value)
    return my_strntoll(value->charset(), value->ptr(),
5783
		       value->length(), 10, (char**) 0, &err);
5784 5785 5786
  else
    return (longlong)0;
}
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5787

5788 5789 5790 5791 5792 5793 5794 5795 5796 5797
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;
}

5798

5799 5800
bool Item_cache_row::allocate(uint num)
{
5801
  item_count= num;
5802
  THD *thd= current_thd;
5803 5804
  return (!(values= 
	    (Item_cache **) thd->calloc(sizeof(Item_cache *)*item_count)));
5805 5806
}

5807

5808 5809
bool Item_cache_row::setup(Item * item)
{
5810
  example= item;
5811 5812
  if (!values && allocate(item->cols()))
    return 1;
5813
  for (uint i= 0; i < item_count; i++)
5814
  {
5815
    Item *el= item->el(i);
5816 5817
    Item_cache *tmp;
    if (!(tmp= values[i]= Item_cache::get_cache(el->result_type())))
5818
      return 1;
5819
    tmp->setup(el);
5820 5821 5822 5823
  }
  return 0;
}

5824

5825 5826 5827 5828
void Item_cache_row::store(Item * item)
{
  null_value= 0;
  item->bring_value();
5829
  for (uint i= 0; i < item_count; i++)
5830 5831 5832 5833 5834 5835
  {
    values[i]->store(item->el(i));
    null_value|= values[i]->null_value;
  }
}

5836

5837 5838 5839 5840 5841
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);
5842
  my_error(ER_OPERAND_COLUMNS, MYF(0), 1);
5843 5844 5845
  DBUG_VOID_RETURN;
}

5846

5847 5848
bool Item_cache_row::check_cols(uint c)
{
5849
  if (c != item_count)
5850
  {
5851
    my_error(ER_OPERAND_COLUMNS, MYF(0), c);
5852 5853 5854 5855 5856
    return 1;
  }
  return 0;
}

5857

5858 5859
bool Item_cache_row::null_inside()
{
5860
  for (uint i= 0; i < item_count; i++)
5861 5862 5863 5864 5865 5866 5867 5868 5869 5870 5871 5872 5873 5874 5875 5876
  {
    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;
}

5877

5878 5879
void Item_cache_row::bring_value()
{
5880
  for (uint i= 0; i < item_count; i++)
5881 5882 5883
    values[i]->bring_value();
  return;
}
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5884

5885

5886 5887
Item_type_holder::Item_type_holder(THD *thd, Item *item)
  :Item(thd, item), enum_set_typelib(0), fld_type(get_real_type(item))
5888 5889
{
  DBUG_ASSERT(item->fixed);
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5890

5891
  max_length= display_length(item);
5892
  maybe_null= item->maybe_null;
5893
  collation.set(item->collation);
5894
  get_full_info(item);
5895 5896 5897
  /* fix variable decimals which always is NOT_FIXED_DEC */
  if (Field::result_merge_type(fld_type) == INT_RESULT)
    decimals= 0;
5898
  prev_decimal_int_part= item->decimal_int_part();
5899 5900 5901
}


5902
/*
5903
  Return expression type of Item_type_holder
5904 5905

  SYNOPSIS
5906
    Item_type_holder::result_type()
5907 5908

  RETURN
5909
     Item_result (type of internal MySQL expression result)
5910 5911
*/

5912
Item_result Item_type_holder::result_type() const
5913
{
5914
  return Field::result_merge_type(fld_type);
5915
}
5916

5917

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5918
/*
5919
  Find real field type of item
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5920 5921

  SYNOPSIS
5922
    Item_type_holder::get_real_type()
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5923 5924

  RETURN
5925
    type of field which should be created to store item value
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5926 5927
*/

5928
enum_field_types Item_type_holder::get_real_type(Item *item)
5929
{
5930
  switch(item->type())
5931
  {
5932
  case FIELD_ITEM:
5933
  {
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5934
    /*
5935 5936
      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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5937
    */
5938 5939 5940 5941 5942 5943
    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;
5944
  }
5945
  case SUM_FUNC_ITEM:
5946
  {
5947 5948 5949 5950
    /*
      Argument of aggregate function sometimes should be asked about field
      type
    */
5951 5952
    Item_sum *item_sum= (Item_sum *) item;
    if (item_sum->keep_field_type())
5953 5954 5955 5956
      return get_real_type(item_sum->args[0]);
    break;
  }
  case FUNC_ITEM:
5957
    if (((Item_func *) item)->functype() == Item_func::GUSERVAR_FUNC)
5958
    {
5959
      /*
5960 5961 5962 5963
        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.
5964
      */
5965
      switch (item->result_type()) {
5966 5967 5968 5969 5970 5971
      case STRING_RESULT:
        return MYSQL_TYPE_VAR_STRING;
      case INT_RESULT:
        return MYSQL_TYPE_LONGLONG;
      case REAL_RESULT:
        return MYSQL_TYPE_DOUBLE;
5972 5973
      case DECIMAL_RESULT:
        return MYSQL_TYPE_NEWDECIMAL;
5974 5975 5976 5977 5978
      case ROW_RESULT:
      default:
        DBUG_ASSERT(0);
        return MYSQL_TYPE_VAR_STRING;
      }
5979
    }
5980 5981 5982
    break;
  default:
    break;
5983
  }
5984
  return item->field_type();
5985 5986
}

5987
/*
5988 5989
  Find field type which can carry current Item_type_holder type and
  type of given Item.
5990 5991

  SYNOPSIS
5992 5993 5994
    Item_type_holder::join_types()
    thd     thread handler
    item    given item to join its parameters with this item ones
5995 5996

  RETURN
5997 5998
    TRUE   error - types are incompatible
    FALSE  OK
5999 6000
*/

6001
bool Item_type_holder::join_types(THD *thd, Item *item)
6002
{
6003 6004
  uint max_length_orig= max_length;
  uint decimals_orig= decimals;
6005 6006 6007 6008 6009 6010 6011
  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));
6012
  fld_type= Field::field_type_merge(fld_type, get_real_type(item));
6013
  {
6014 6015 6016 6017 6018
    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);
6019
  }
6020
  if (Field::result_merge_type(fld_type) == DECIMAL_RESULT)
6021
  {
6022 6023 6024 6025 6026 6027
    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);
6028
  }
6029 6030
  else
    max_length= max(max_length, display_length(item));
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6031
 
6032 6033 6034
  switch (Field::result_merge_type(fld_type))
  {
  case STRING_RESULT:
6035
  {
6036
    const char *old_cs, *old_derivation;
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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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    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:;
  };
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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
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  SYNOPSIS
    Item_type_holder::real_length()
    item  Item for lrngth detection
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  RETURN
    length
*/
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uint32 Item_type_holder::display_length(Item *item)
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{
  if (item->type() == Item::FIELD_ITEM)
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    return ((Item_field *)item)->max_disp_length();
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  switch (item->field_type())
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  {
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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:
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    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;
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  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;
  }
}
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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)
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  {
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  case MYSQL_TYPE_ENUM:
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    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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    /*
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      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;
    }
  }
}


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

6279
#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>;
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template class List_iterator_fast<Item_field>;
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template class List<List_item>;
#endif