Fixed that NULL and 0 returns 0 instead of NULL

This is coded to not cause a speed impact on top level AND expressions where we don't care if an AND expression returns 0 or NULL

mysql-test/r/bdb.result

@@ -203,7 +203,7 @@ a
 2
 check table t1;
 Table	Op	Msg_type	Msg_text
-test.t1	check	error	The handler for the table doesn't support check/repair
+test.t1	check	error	The handler for the table doesn't support check
 drop table t1;
 create table t1 (a int,b varchar(20)) type=bdb;
 insert into t1 values (1,""), (2,"testing");

mysql-test/r/bool.result

+DROP TABLE IF EXISTS t1;
+SELECT IF(NULL AND 1, 1, 2), IF(1 AND NULL, 1, 2);
+IF(NULL AND 1, 1, 2)	IF(1 AND NULL, 1, 2)
+2	2
+SELECT NULL AND 1, 1 AND NULL, 0 AND NULL, NULL and 0;
+NULL AND 1	1 AND NULL	0 AND NULL	NULL and 0
+NULL	NULL	0	0
+create table t1 (a int);
+insert into t1 values (0),(1),(NULL);
+SELECT * FROM t1 WHERE IF(a AND 1, 0, 1);
+a
+0
+NULL
+SELECT * FROM t1 WHERE IF(1 AND a, 0, 1);
+a
+0
+NULL
+SELECT * FROM t1 where NOT(a AND 1);
+a
+0
+SELECT * FROM t1 where NOT(1 AND a);
+a
+0
+SELECT * FROM t1 where (a AND 1)=0;
+a
+0
+SELECT * FROM t1 where (1 AND a)=0;
+a
+0
+SELECT * FROM t1 where (1 AND a)=1;
+a
+1
+SELECT * FROM t1 where (1 AND a) IS NULL;
+a
+NULL
+SET @a=0, @b=0;
+SELECT * FROM t1 WHERE NULL AND (@a:=@a+1);
+a
+SELECT * FROM t1 WHERE NOT(a>=0 AND NULL AND (@b:=@b+1));
+a
+SELECT * FROM t1 WHERE a=2 OR (NULL AND (@a:=@a+1));
+a
+SELECT * FROM t1 WHERE NOT(a=2 OR (NULL AND (@b:=@b+1)));
+a
+SELECT @a, @b;
+@a	@b
+0	6
+DROP TABLE t1;

mysql-test/r/innodb.result

@@ -165,7 +165,7 @@ level	id	parent_id
 1	1007	101
 optimize table t1;
 Table	Op	Msg_type	Msg_text
-test.t1	optimize	error	The handler for the table doesn't support check/repair
+test.t1	optimize	error	The handler for the table doesn't support optimize
 show keys from t1;
 Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment
 t1	0	PRIMARY	1	id	A	87	NULL	NULL		BTREE	
@@ -189,7 +189,7 @@ create table t1 (a int) type=innodb;
 insert into t1 values (1), (2);
 optimize table t1;
 Table	Op	Msg_type	Msg_text
-test.t1	optimize	error	The handler for the table doesn't support check/repair
+test.t1	optimize	error	The handler for the table doesn't support optimize
 delete from t1 where a = 1;
 select * from t1;
 a
@@ -208,7 +208,7 @@ create index skr on t1 (a);
 insert into t1 values (3,""), (4,"testing");
 analyze table t1;
 Table	Op	Msg_type	Msg_text
-test.t1	analyze	error	The handler for the table doesn't support check/repair
+test.t1	analyze	error	The handler for the table doesn't support analyze
 show keys from t1;
 Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment
 t1	1	skr	1	a	A	3	NULL	NULL	YES	BTREE	
@@ -724,7 +724,7 @@ world	2
 hello	1
 optimize table t1;
 Table	Op	Msg_type	Msg_text
-test.t1	optimize	error	The handler for the table doesn't support check/repair
+test.t1	optimize	error	The handler for the table doesn't support optimize
 show keys from t1;
 Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment
 t1	0	PRIMARY	1	a	A	2	NULL	NULL		BTREE	

mysql-test/r/null.result

@@ -30,7 +30,7 @@ SELECT (NULL OR NULL) IS NULL;
 1
 select NULL AND 0, 0 and NULL;
 NULL AND 0	0 and NULL
-NULL	0
+0	0
 select inet_ntoa(null),inet_aton(null),inet_aton("122.256"),inet_aton("122.226."),inet_aton("");
 inet_ntoa(null)	inet_aton(null)	inet_aton("122.256")	inet_aton("122.226.")	inet_aton("")
 NULL	NULL	NULL	NULL	NULL

mysql-test/t/bool.test

+#
+# Test of boolean operations with NULL
+#
+
+DROP TABLE IF EXISTS t1;
+
+SELECT IF(NULL AND 1, 1, 2), IF(1 AND NULL, 1, 2);
+SELECT NULL AND 1, 1 AND NULL, 0 AND NULL, NULL and 0;
+
+create table t1 (a int);
+insert into t1 values (0),(1),(NULL);
+SELECT * FROM t1 WHERE IF(a AND 1, 0, 1);
+SELECT * FROM t1 WHERE IF(1 AND a, 0, 1);
+SELECT * FROM t1 where NOT(a AND 1);
+SELECT * FROM t1 where NOT(1 AND a);
+SELECT * FROM t1 where (a AND 1)=0;
+SELECT * FROM t1 where (1 AND a)=0;
+SELECT * FROM t1 where (1 AND a)=1;
+SELECT * FROM t1 where (1 AND a) IS NULL;
+
+# Verify that NULL optimisation works in AND clause:
+SET @a=0, @b=0;
+SELECT * FROM t1 WHERE NULL AND (@a:=@a+1);
+SELECT * FROM t1 WHERE NOT(a>=0 AND NULL AND (@b:=@b+1));
+SELECT * FROM t1 WHERE a=2 OR (NULL AND (@a:=@a+1));
+SELECT * FROM t1 WHERE NOT(a=2 OR (NULL AND (@b:=@b+1)));
+SELECT @a, @b;
+DROP TABLE t1;

scripts/mysqld_safe.sh

@@ -204,7 +204,7 @@ else
 fi
 
 USER_OPTION=""
-if test "x$USER" = "xroot"
+if test -w / -o "$USER" = "root"
 then
   if test "$user" != "root" -o $SET_USER = 1
   then

sql/item.h

@@ -85,6 +85,7 @@ class Item {
   virtual bool get_time(TIME *ltime);
   virtual bool is_null() { return 0; }
   virtual unsigned int size_of()= 0;
+  virtual void top_level_item() {}
 };
 
 

sql/item_cmpfunc.cc

@@ -26,8 +26,8 @@
 
 /*
   Test functions
-  These returns 0LL if false and 1LL if true and null if some arg is null
-  'AND' and 'OR' never return null
+  Most of these  returns 0LL if false and 1LL if true and
+  NULL if some arg is NULL.
 */
 
 longlong Item_func_not::val_int()
@@ -533,6 +533,7 @@ Item_func_if::fix_length_and_dec()
     else
       cached_result_type=arg1_type;		// Should be INT_RESULT
   }
+  args[0]->top_level_item();
 }
 
 
@@ -1128,6 +1129,8 @@ Item_cond::fix_fields(THD *thd,TABLE_LIST *tables)
     const_item_cache&=item->const_item();
     if (item->maybe_null)
       maybe_null=1;
+    if (abort_on_null)
+      item->top_level_item();
   }
   if (thd)
     thd->cond_count+=list.elements;
@@ -1196,28 +1199,41 @@ void Item_cond::print(String *str)
   str->append(')');
 }
 
+/*
+  Evalution of AND(expr, expr, expr ...)
+
+  NOTES:
+    abort_if_null is set for AND expressions for which we don't care if the
+    result is NULL or 0. This is set for:
+    - WHERE clause
+    - HAVING clause
+    - IF(expression)
+
+  RETURN VALUES
+    1  If all expressions are true
+    0  If all expressions are false or if we find a NULL expression and
+       'abort_on_null' is set.
+    NULL if all expression are either 1 or NULL
+*/
+
 
 longlong Item_cond_and::val_int()
 {
   List_iterator_fast<Item> li(list);
   Item *item;
+  null_value= 0;
   while ((item=li++))
   {
     if (item->val_int() == 0)
     {
-      /*
-	TODO: In case of NULL, ANSI would require us to continue evaluation
-	until we get a FALSE value or run out of values; This would
-	require a lot of unnecessary evaluation, which we skip for now
-      */
-      null_value=item->null_value;
-      return 0;
+      if (abort_on_null || !(null_value= item->null_value))
+	return 0;				// return FALSE
     }
   }
-  null_value=0;
-  return 1;
+  return null_value ? 0 : 1;
 }
 
+
 longlong Item_cond_or::val_int()
 {
   List_iterator_fast<Item> li(list);
@@ -1260,15 +1276,15 @@ longlong Item_cond_or::val_int()
 Item *and_expressions(Item *a, Item *b, Item **org_item)
 {
   if (!a)
-    return (*org_item= (Item*) b);
+    return (*org_item= b);
   if (a == *org_item)
   {
     Item_cond *res;
-    if ((res= new Item_cond_and(a, (Item*) b)))
+    if ((res= new Item_cond_and(a, b)))
       res->used_tables_cache= a->used_tables() | b->used_tables();
     return res;
   }
-  if (((Item_cond_and*) a)->add((Item*) b))
+  if (((Item_cond_and*) a)->add(b))
     return 0;
   ((Item_cond_and*) a)->used_tables_cache|= b->used_tables();
   return a;

sql/item_cmpfunc.h

@@ -560,9 +560,11 @@ class Item_cond :public Item_bool_func
 {
 protected:
   List<Item> list;
+  bool abort_on_null;
 public:
-  Item_cond() : Item_bool_func() { const_item_cache=0; }
-  Item_cond(Item *i1,Item *i2) :Item_bool_func()
+  /* Item_cond() is only used to create top level items */
+  Item_cond() : Item_bool_func(), abort_on_null(1) { const_item_cache=0; }
+  Item_cond(Item *i1,Item *i2) :Item_bool_func(), abort_on_null(0)
   { list.push_back(i1); list.push_back(i2); }
   ~Item_cond() { list.delete_elements(); }
   bool add(Item *item) { return list.push_back(item); }
@@ -576,6 +578,7 @@ class Item_cond :public Item_bool_func
   void split_sum_func(List<Item> &fields);
   friend int setup_conds(THD *thd,TABLE_LIST *tables,COND **conds);
   unsigned int size_of() { return sizeof(*this);}  
+  void top_level_item() { abort_on_null=1; }
 };
 
 

sql/sql_base.cc

@@ -1976,6 +1976,7 @@ int setup_conds(THD *thd,TABLE_LIST *tables,COND **conds)
       Item_cond_and *cond_and=new Item_cond_and();
       if (!cond_and)				// If not out of memory
 	DBUG_RETURN(1);
+      cond_and->top_level_item();
 
       uint i,j;
       for (i=0 ; i < t1->fields ; i++)

sql/sql_parse.cc

@@ -3324,6 +3324,8 @@ static bool create_total_list(THD *thd, LEX *lex, TABLE_LIST **result)
 
 void add_join_on(TABLE_LIST *b,Item *expr)
 {
+  if (expr)
+  {
     if (!b->on_expr)
       b->on_expr=expr;
     else
@@ -3331,6 +3333,8 @@ void add_join_on(TABLE_LIST *b,Item *expr)
       // This only happens if you have both a right and left join
       b->on_expr=new Item_cond_and(b->on_expr,expr);
     }
+    b->on_expr->top_level_item();
+  }
 }
 
 

sql/sql_select.cc

@@ -360,6 +360,7 @@ mysql_select(THD *thd,TABLE_LIST *tables,List<Item> &fields,COND *conds,
     {
       conds->fix_fields(thd,tables);
       conds->change_ref_to_fields(thd,tables);
+      conds->top_level_item();
       having=0;
     }
   }
@@ -869,6 +870,7 @@ mysql_select(THD *thd,TABLE_LIST *tables,List<Item> &fields,COND *conds,
 						      sort_table_cond)))
 	    goto err;
 	table->select_cond=table->select->cond;
+	table->select_cond->top_level_item();
 	DBUG_EXECUTE("where",print_where(table->select->cond,
 					 "select and having"););
 	having=make_cond_for_table(having,~ (table_map) 0,~used_tables);
@@ -5490,6 +5492,7 @@ make_cond_for_table(COND *cond,table_map tables,table_map used_table)
   {
     if (((Item_cond*) cond)->functype() == Item_func::COND_AND_FUNC)
     {
+      /* Create new top level AND item */
       Item_cond_and *new_cond=new Item_cond_and;
       if (!new_cond)
 	DBUG_RETURN((COND*) 0);			// OOM /* purecov: inspected */
@@ -5527,6 +5530,7 @@ make_cond_for_table(COND *cond,table_map tables,table_map used_table)
 	new_cond->argument_list()->push_back(fix);
       }
       new_cond->used_tables_cache=((Item_cond_or*) cond)->used_tables_cache;
+      new_cond->top_level_item();
       DBUG_RETURN(new_cond);
     }
   }
@@ -5886,6 +5890,7 @@ static bool fix_having(JOIN *join, Item **having)
 						  sort_table_cond)))
 	DBUG_RETURN(1);
     table->select_cond=table->select->cond;
+    table->select_cond->top_level_item();
     DBUG_EXECUTE("where",print_where(table->select_cond,
 				     "select and having"););
     *having=make_cond_for_table(*having,~ (table_map) 0,~used_tables);

sql/sql_yacc.yy

@@ -2178,15 +2178,25 @@ opt_table_alias:
 
 where_clause:
 	/* empty */  { Select->where= 0; }
-	| WHERE expr { Select->where= $2; };
+	| WHERE expr
+	  {
+	    Select->where= $2;
+	    if ($2)
+	      $2->top_level_item();
+	  }
+	  ;
 
 having_clause:
 	/* empty */
 	| HAVING { Select->create_refs=1; } expr
 	{
 	  SELECT_LEX *sel=Select;
-	  sel->having= $3; sel->create_refs=0;
-	};
+	  sel->having= $3;
+	  sel->create_refs=0;
+	  if ($3)
+	    $3->top_level_item();
+	}
+	;
 
 opt_escape:
 	ESCAPE_SYM TEXT_STRING	{ $$= $2.str; }