after review patch

mysql-test/r/negation_elimination.result

@@ -375,4 +375,17 @@ a
 13
 14
 15
+delete from t1 where a > 3;
+select a, not(not(a)) from t1;
+a	not(not(a))
+NULL	NULL
+0	0
+1	1
+2	1
+3	1
+explain extended select a, not(not(a)), not(a <= 2 and not(a)), not(a not like "1"), not (a not in (1,2)), not(a != 2) from t1 where not(not(a)) having not(not(a));
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	index	NULL	a	5	NULL	5	Using where; Using index
+Warnings:
+Note	1003	select test.t1.a AS `a`,(test.t1.a <> 0) AS `not(not(a))`,((test.t1.a > 2) or test.t1.a) AS `not(a <= 2 and not(a))`,(test.t1.a like _latin1'1') AS `not(a not like "1")`,(test.t1.a in (1,2)) AS `not (a not in (1,2))`,(test.t1.a = 2) AS `not(a != 2)` from test.t1 where test.t1.a having test.t1.a
 drop table t1;

mysql-test/t/negation_elimination.test

@@ -65,4 +65,8 @@ select * from t1 where not((a < 5 and a < 10) and (not(a > 16) or a > 17));
 explain select * from t1 where ((a between 5 and 15) and (not(a like 10)));
 select * from t1 where ((a between 5 and 15) and (not(a like 10)));
 
+delete from t1 where a > 3;
+select a, not(not(a)) from t1;
+explain extended select a, not(not(a)), not(a <= 2 and not(a)), not(a not like "1"), not (a not in (1,2)), not(a != 2) from t1 where not(not(a)) having not(not(a));
+
 drop table t1;

sql/item.h

@@ -239,6 +239,7 @@ class Item {
   virtual void top_level_item() {}
   virtual void set_result_field(Field *field) {}
   virtual bool is_result_field() { return 0; }
+  virtual bool is_bool_func() { return 0; }
   virtual void save_in_result_field(bool no_conversions) {}
   virtual void no_rows_in_result() {}
   virtual Item *copy_or_same(THD *thd) { return this; }
@@ -268,8 +269,7 @@ class Item {
   virtual void bring_value() {}
 
   Field *tmp_table_field_from_field_type(TABLE *table);
-  
-  /* Used in sql_select.cc:eliminate_not_funcs() */
+
   virtual Item *neg_transformer(THD *thd) { return NULL; }
   void delete_self()
   {

sql/item_cmpfunc.cc

@@ -2707,9 +2707,6 @@ longlong Item_cond_xor::val_int()
        IS NULL(a)         -> IS NOT NULL(a)
        IS NOT NULL(a)     -> IS NULL(a)
 
-  NOTE
-    This method is used in the eliminate_not_funcs() function.
-
   RETURN
     New item or
     NULL if we cannot apply NOT transformation (see Item::neg_transformer()).
@@ -2718,7 +2715,7 @@ longlong Item_cond_xor::val_int()
 Item *Item_func_not::neg_transformer(THD *thd)	/* NOT(x)  ->  x */
 {
   // We should apply negation elimination to the argument of the NOT function
-  return eliminate_not_funcs(thd, args[0]);
+  return args[0];
 }
 
 

sql/item_cmpfunc.h

@@ -89,6 +89,7 @@ class Item_bool_func :public Item_int_func
   Item_bool_func(Item *a) :Item_int_func(a) {}
   Item_bool_func(Item *a,Item *b) :Item_int_func(a,b) {}
   Item_bool_func(THD *thd, Item_bool_func *item) :Item_int_func(thd, item) {}
+  bool is_bool_func() { return 1; }
   void fix_length_and_dec() { decimals=0; max_length=1; }
 };
 
@@ -201,6 +202,7 @@ class Item_bool_func2 :public Item_int_func
   bool have_rev_func() const { return rev_functype() != UNKNOWN_FUNC; }
   void print(String *str) { Item_func::print_op(str); }
   bool is_null() { return test(args[0]->is_null() || args[1]->is_null()); }
+  bool is_bool_func() { return 1; }
   CHARSET_INFO *compare_collation() { return cmp.cmp_collation.collation; }
 
   friend class  Arg_comparator;
@@ -748,6 +750,7 @@ class Item_func_in :public Item_int_func
   enum Functype functype() const { return IN_FUNC; }
   const char *func_name() const { return " IN "; }
   bool nulls_in_row();
+  bool is_bool_func() { return 1; }
   CHARSET_INFO *compare_collation() { return cmp_collation.collation; }
 };
 

sql/mysql_priv.h

@@ -297,7 +297,8 @@ enum enum_parsing_place
 {
   NO_MATTER,
   IN_HAVING,
-  SELECT_LIST
+  SELECT_LIST,
+  IN_WHERE
 };
 
 struct st_table;
@@ -376,6 +377,7 @@ int delete_precheck(THD *thd, TABLE_LIST *tables);
 int insert_precheck(THD *thd, TABLE_LIST *tables, bool update);
 int create_table_precheck(THD *thd, TABLE_LIST *tables,
 			  TABLE_LIST *create_table);
+Item *negate_expression(THD *thd, Item *expr);
 #include "sql_class.h"
 #include "opt_range.h"
 

sql/sql_parse.cc

@@ -5401,3 +5401,39 @@ int create_table_precheck(THD *thd, TABLE_LIST *tables,
 	       check_grant(thd, want_priv, create_table, 0, UINT_MAX, 0)) ?
 	      1 : 0);
 }
+
+
+/*
+  negate given expression
+
+  SYNOPSIS
+    negate_expression()
+    thd  therad handler
+    expr expression for negation
+
+  RETURN
+    negated expression
+*/
+
+Item *negate_expression(THD *thd, Item *expr)
+{
+  Item *negated;
+  if (expr->type() == Item::FUNC_ITEM &&
+      ((Item_func *) expr)->functype() == Item_func::NOT_FUNC)
+  {
+    /* it is NOT(NOT( ... )) */
+    Item *arg= ((Item_func *) expr)->arguments()[0];
+    enum_parsing_place place= thd->lex->current_select->parsing_place;
+    if (arg->is_bool_func() || place == IN_WHERE || place == IN_HAVING)
+      return arg;
+    /*
+      if it is not boolean function then we have to emulate value of
+      not(not(a)), it will be a != 0
+    */
+    return new Item_func_ne(arg, new Item_int((char*) "0", 0, 1));
+  }
+
+  if ((negated= expr->neg_transformer(thd)) != 0)
+    return negated;
+  return new Item_func_not(expr);
+}

sql/sql_select.cc

@@ -4339,60 +4339,6 @@ propagate_cond_constants(I_List<COND_CMP> *save_list,COND *and_father,
 }
 
 
-/*
-  Eliminate NOT functions from the condition tree.
-
-  SYNPOSIS
-    eliminate_not_funcs()
-    thd		thread handler
-    cond	condition tree
-
-  DESCRIPTION
-    Eliminate NOT functions from the condition tree where it's possible.
-    Recursively traverse condition tree to find all NOT functions.
-    Call neg_transformer() method for negated arguments.
-
-  NOTE
-    If neg_transformer() returned a new condition we call fix_fields().
-    We don't delete any items as it's not needed. They will be deleted 
-    later at once.
-
-  RETURN
-    New condition tree
-*/
-
-COND *eliminate_not_funcs(THD *thd, COND *cond)
-{
-  if (!cond)
-    return cond;
-  if (cond->type() == Item::COND_ITEM)		/* OR or AND */
-  {
-    List_iterator<Item> li(*((Item_cond*) cond)->argument_list());
-    Item *item;
-    while ((item= li++))
-    {
-      Item *new_item= eliminate_not_funcs(thd, item);
-      if (item != new_item)
-	VOID(li.replace(new_item));	/* replace item with a new condition */
-    }
-  }
-  else if (cond->type() == Item::FUNC_ITEM &&	/* 'NOT' operation? */
-	   ((Item_func*) cond)->functype() == Item_func::NOT_FUNC)
-  {
-    COND *new_cond= ((Item_func*) cond)->arguments()[0]->neg_transformer(thd);
-    if (new_cond)
-    {
-      /*
-        Here we can delete the NOT function. Something like: delete cond;
-        But we don't need to do it. All items will be deleted later at once.
-      */
-      cond= new_cond;
-    }
-  }
-  return cond;
-}
-
-
 static COND *
 optimize_cond(THD *thd, COND *conds, Item::cond_result *cond_value)
 {

sql/sql_select.h

@@ -438,4 +438,3 @@ bool cp_buffer_from_ref(TABLE_REF *ref);
 bool error_if_full_join(JOIN *join);
 int report_error(TABLE *table, int error);
 int safe_index_read(JOIN_TAB *tab);
-COND *eliminate_not_funcs(THD *thd, COND *cond);

sql/sql_yacc.yy

@@ -2757,13 +2757,11 @@ simple_expr:
 	| '~' expr %prec NEG	{ $$= new Item_func_bit_neg($2); }
 	| NOT expr %prec NEG
           {
-            if (($$= $2->neg_transformer(YYTHD)) == 0)
-              $$= new Item_func_not($2);
+            $$= negate_expression(YYTHD, $2);
           }
 	| '!' expr %prec NEG
           {
-            if (($$= $2->neg_transformer(YYTHD)) == 0)
-              $$= new Item_func_not($2);
+            $$= negate_expression(YYTHD, $2);
           }
 	| '(' expr ')'		{ $$= $2; }
 	| '(' expr ',' expr_list ')'
@@ -3606,11 +3604,17 @@ opt_all:
 
 where_clause:
 	/* empty */  { Select->where= 0; }
-	| WHERE expr
+	| WHERE
+          {
+            Select->parsing_place= IN_WHERE;
+          }
+          expr
 	  {
-	    Select->where= $2;
-	    if ($2)
-	      $2->top_level_item();
+            SELECT_LEX *select= Select;
+	    select->where= $3;
+            select->parsing_place= NO_MATTER;
+	    if ($3)
+	      $3->top_level_item();
 	  }
  	;