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fixed bug 185 (constant IN (SELECT field ...) do not return NULL correctly)

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mysql-test/r/subselect.result:
  new test results
  test of bug 185
mysql-test/t/subselect.test:
  test of bug 185
sql/item.h:
  new method
sql/item_cmpfunc.cc:
  new Item to control NULL value in HAVING clouse
sql/item_cmpfunc.h:
  new Item to control NULL value in HAVING clouse
sql/item_subselect.cc:
  if IN was rewrited through WHERE thien it will be rewrited in following way:
  
  WHERE left_expr=item or is null(item) heving is_not_null_test(item)
sql/item_subselect.h:
  Item_is_not_null_test can change was_null flag
sql/sql_select.cc:
  some layout fix
This commit is contained in:
unknown
2003-04-23 00:01:19 +03:00
parent 1db8654191
commit 06017a0db0
8 changed files with 103 additions and 10 deletions
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12
mysql-test/r/subselect.result
View File

@ -810,7 +810,7 @@ a t1.a in (select t2.a from t2)
explain SELECT t1.a, t1.a in (select t2.a from t2) FROM t1;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 index NULL PRIMARY 4 NULL 4 Using index
2 DEPENDENT SUBQUERY t2 index NULL a 5 NULL 3 Using where; Using index
2 DEPENDENT SUBQUERY t2 index a a 5 NULL 3 Using where; Using index
drop table t1,t2;
create table t1 (a float);
select 10.5 IN (SELECT * from t1 LIMIT 1);
@ -1062,7 +1062,7 @@ SELECT 0 IN (SELECT 1 FROM t1 a);
EXPLAIN SELECT 0 IN (SELECT 1 FROM t1 a);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL No tables used
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
INSERT INTO t1 (pseudo) VALUES ('test1');
SELECT 0 IN (SELECT 1 FROM t1 a);
0 IN (SELECT 1 FROM t1 a)
@ -1070,7 +1070,7 @@ SELECT 0 IN (SELECT 1 FROM t1 a);
EXPLAIN SELECT 0 IN (SELECT 1 FROM t1 a);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL No tables used
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
drop table t1;
CREATE TABLE `t1` (
`i` int(11) NOT NULL default '0',
@ -1099,3 +1099,9 @@ id name
2 lenka
1 lenka
drop table t1,t2;
create table t1 (a int, unique index indexa (a));
insert into t1 values (-1), (-4), (-2), (NULL);
select -10 IN (select a from t1 FORCE INDEX (indexa));
-10 IN (select a from t1 FORCE INDEX (indexa))
NULL
drop table t1;

8
mysql-test/t/subselect.test
View File

@ -690,3 +690,11 @@ INSERT INTO t2 VALUES (4,'vita'), (1,'vita'), (2,'vita'), (1,'vita');
update t1, t2 set t2.name='lenka' where t2.id in (select id from t1);
select * from t2;
drop table t1,t2;
#
# correct NULL in <CONSTANT> IN (SELECT ...)
#
create table t1 (a int, unique index indexa (a));
insert into t1 values (-1), (-4), (-2), (NULL);
select -10 IN (select a from t1 FORCE INDEX (indexa));
drop table t1;

1
sql/item.h
View File

@ -603,6 +603,7 @@ public:
item(it)
{}
bool fix_fields(THD *, struct st_table_list *, Item ** ref);
Item **storage() {return &item;}
};
/*

37
sql/item_cmpfunc.cc
View File

@ -1781,6 +1781,43 @@ longlong Item_func_isnull::val_int()
return args[0]->is_null() ? 1: 0;
}
longlong Item_is_not_null_test::val_int()
{
DBUG_ENTER("Item_is_not_null_test::val_int");
if (!used_tables_cache)
{
owner->was_null|= (!cached_value);
DBUG_PRINT("info", ("cached :%d", cached_value));
DBUG_RETURN(cached_value);
}
if (args[0]->is_null())
{
DBUG_PRINT("info", ("null"))
owner->was_null|= 1;
DBUG_RETURN(0);
}
else
DBUG_RETURN(1);
}
/* Optimize case of not_null_column IS NULL */
void Item_is_not_null_test::update_used_tables()
{
if (!args[0]->maybe_null)
{
used_tables_cache= 0; /* is always true */
cached_value= (longlong) 1;
}
else
{
args[0]->update_used_tables();
if (!(used_tables_cache=args[0]->used_tables()))
{
/* Remember if the value is always NULL or never NULL */
cached_value= (longlong) !args[0]->is_null();
}
}
}
longlong Item_func_isnotnull::val_int()
{

21
sql/item_cmpfunc.h
View File

@ -648,6 +648,7 @@ class Item_func_in :public Item_int_func
class Item_func_isnull :public Item_bool_func
{
protected:
longlong cached_value;
public:
Item_func_isnull(Item *a) :Item_bool_func(a) {}
@ -656,11 +657,11 @@ public:
void fix_length_and_dec()
{
decimals=0; max_length=1; maybe_null=0;
Item_func_isnull::update_used_tables();
update_used_tables();
}
const char *func_name() const { return "isnull"; }
/* Optimize case of not_null_column IS NULL */
void update_used_tables()
virtual void update_used_tables()
{
if (!args[0]->maybe_null)
{
@ -680,6 +681,22 @@ public:
optimize_type select_optimize() const { return OPTIMIZE_NULL; }
};
/* Functions used by HAVING for rewriting IN subquery */
class Item_in_subselect;
class Item_is_not_null_test :public Item_func_isnull
{
Item_in_subselect* owner;
public:
Item_is_not_null_test(Item_in_subselect* ow, Item *a)
:Item_func_isnull(a), owner(ow)
{}
longlong val_int();
const char *func_name() const { return "is_not_null_test"; }
void update_used_tables();
};
class Item_func_isnotnull :public Item_bool_func
{
public:

28
sql/item_subselect.cc
View File

@ -508,9 +508,31 @@ void Item_in_subselect::single_value_transformer(THD *thd,
sl->item_list.push_back(new Item_int("Not_used", (longlong) 1, 21));
if (sl->table_list.elements)
{
item= (*func)(expr, new Item_asterisk_remover(this, item,
(char *)"<no matter>",
(char*)"<result>"));
Item *having= item, *isnull= item;
if (item->type() == Item::FIELD_ITEM &&
((Item_field*) item)->field_name[0] == '*')
{
Item_asterisk_remover *remover;
item= remover= new Item_asterisk_remover(this, item,
(char*)"<no matter>",
(char*)"<result>");
having=
new Item_is_not_null_test(this,
new Item_ref(remover->storage(),
(char*)"<no matter>",
(char*)"<null test>"));
isnull=
new Item_is_not_null_test(this,
new Item_ref(remover->storage(),
(char*)"<no matter>",
(char*)"<null test>"));
}
having= new Item_is_not_null_test(this, having);
sl->having= (sl->having ?
new Item_cond_and(having, sl->having) :
having);
item= new Item_cond_or((*func)(expr, item),
new Item_func_isnull(isnull));
sl->where= and_items(sl->where, item);
}
else

1
sql/item_subselect.h
View File

@ -183,6 +183,7 @@ public:
friend class Item_asterisk_remover;
friend class Item_ref_null_helper;
friend class Item_is_not_null_test;
};
/* ALL/ANY/SOME subselect */

3
sql/sql_select.cc
View File

@ -313,6 +313,7 @@ JOIN::prepare(Item ***rref_pointer_array,
if (having->with_sum_func)
having->split_sum_func(ref_pointer_array, all_fields);
}
if (setup_ftfuncs(select_lex)) /* should be after having->fix_fields */
DBUG_RETURN(-1);
/*
@ -426,7 +427,7 @@ JOIN::optimize()
#ifdef HAVE_REF_TO_FIELDS // Not done yet
/* Add HAVING to WHERE if possible */
if (having && !group_list && ! sum_func_count)
if (having && !group_list && !sum_func_count)
{
if (!conds)
{