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Fixed mdev-14911: zero_date is considered as NULL, depending on

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optimizer_switch

For DATE and DATETIME columns defined as NOT NULL,
"date_notnull IS NULL" has to be modified to:
"date_notnull IS NULL OR date_notnull == 0"
if date_notnull is from an inner table of outer join);
"date_notnull == 0" - otherwise.

This must hold for such columns of mergeable views and derived
tables as well. So far the code did the above re-writing only
for columns of base tables and temporary tables.
This commit is contained in:
Igor Babaev 2018-01-12 15:51:10 -08:00
parent d8001106c9
commit 6267be460a
3 changed files with 135 additions and 5 deletions
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84
mysql-test/r/func_isnull.result
View File

@ -24,3 +24,87 @@ INSERT INTO t1( id ) VALUES ( NULL );
SELECT t1.id FROM t1 WHERE (id is not null and id is null );
id
DROP TABLE t1;
# End of 5.1 tests
#
# MDEV-14911: IS NULL for field from mergeable view
#
CREATE TABLE t1 (d1 datetime NOT NULL);
INSERT INTO t1 VALUES
('0000-00-00 00:00:00'), ('0000-00-00 00:00:00'), ('1979-09-03 20:49:36');
SELECT * FROM t1;
d1
0000-00-00 00:00:00
0000-00-00 00:00:00
1979-09-03 20:49:36
SELECT * FROM t1 WHERE d1 IS NULL;
d1
0000-00-00 00:00:00
0000-00-00 00:00:00
EXPLAIN EXTENDED SELECT * FROM t1 WHERE d1 IS NULL;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 3 100.00 Using where
Warnings:
Note 1003 select `test`.`t1`.`d1` AS `d1` from `test`.`t1` where (`test`.`t1`.`d1` = 0)
SELECT count(*) FROM t1 WHERE d1 IS NULL;
count(*)
2
CREATE VIEW v1 AS (SELECT * FROM t1);
SELECT * FROM v1;
d1
0000-00-00 00:00:00
0000-00-00 00:00:00
1979-09-03 20:49:36
SELECT * FROM v1 WHERE d1 IS NULL;
d1
0000-00-00 00:00:00
0000-00-00 00:00:00
EXPLAIN EXTENDED SELECT * FROM v1 WHERE d1 IS NULL;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 3 100.00 Using where
Warnings:
Note 1003 select `test`.`t1`.`d1` AS `d1` from `test`.`t1` where (`test`.`t1`.`d1` = 0)
SELECT count(*) FROM v1 WHERE d1 IS NULL;
count(*)
2
SET @save_optimizer_switch=@@optimizer_switch;
SET SESSION optimizer_switch='derived_merge=off';
SELECT count(*) FROM ( SELECT * FROM t1 ) AS a1 WHERE d1 IS NULL;
count(*)
2
SET SESSION optimizer_switch='derived_merge=on';
SELECT count(*) FROM ( SELECT * FROM t1 ) AS a1 WHERE d1 IS NULL;
count(*)
2
SET optimizer_switch=@save_optimizer_switch;
CREATE TABLE t2 (d1 datetime NOT NULL);
INSERT INTO t2 VALUES
('1980-09-03 20:49:36'), ('0000-00-00 00:00:00'), ('1979-09-03 20:49:36');
SELECT * FROM t2 LEFT JOIN t1 ON t2.d1=t1.d1 WHERE t1.d1 IS NULL;
d1 d1
0000-00-00 00:00:00 0000-00-00 00:00:00
0000-00-00 00:00:00 0000-00-00 00:00:00
1980-09-03 20:49:36 NULL
EXPLAIN EXTENDED
SELECT * FROM t2 LEFT JOIN t1 ON t2.d1=t1.d1 WHERE t1.d1 IS NULL;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 3 100.00
1 SIMPLE t1 ALL NULL NULL NULL NULL 3 100.00 Using where; Using join buffer (flat, BNL join)
Warnings:
Note 1003 select `test`.`t2`.`d1` AS `d1`,`test`.`t1`.`d1` AS `d1` from `test`.`t2` left join `test`.`t1` on((`test`.`t1`.`d1` = `test`.`t2`.`d1`)) where ((`test`.`t1`.`d1` = 0) or isnull(`test`.`t1`.`d1`))
SELECT * FROM t2 LEFT JOIN v1 ON t2.d1=v1.d1 WHERE v1.d1 IS NULL;
d1 d1
0000-00-00 00:00:00 0000-00-00 00:00:00
0000-00-00 00:00:00 0000-00-00 00:00:00
1980-09-03 20:49:36 NULL
EXPLAIN EXTENDED
SELECT * FROM t2 LEFT JOIN v1 ON t2.d1=v1.d1 WHERE v1.d1 IS NULL;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 3 100.00
1 SIMPLE t1 ALL NULL NULL NULL NULL 3 100.00 Using where; Using join buffer (flat, BNL join)
Warnings:
Note 1003 select `test`.`t2`.`d1` AS `d1`,`test`.`t1`.`d1` AS `d1` from `test`.`t2` left join (`test`.`t1`) on((`test`.`t1`.`d1` = `test`.`t2`.`d1`)) where ((`test`.`t1`.`d1` = 0) or isnull(`test`.`t1`.`d1`))
DROP VIEW v1;
DROP TABLE t1,t2;
#
# End of 5.5 tests
#

48
mysql-test/t/func_isnull.test
View File

@ -38,5 +38,51 @@ INSERT INTO t1( id ) VALUES ( NULL );
SELECT t1.id FROM t1 WHERE (id is not null and id is null );
DROP TABLE t1;
# End of 5.1 tests
--echo # End of 5.1 tests
--echo #
--echo # MDEV-14911: IS NULL for field from mergeable view
--echo #
CREATE TABLE t1 (d1 datetime NOT NULL);
INSERT INTO t1 VALUES
('0000-00-00 00:00:00'), ('0000-00-00 00:00:00'), ('1979-09-03 20:49:36');
SELECT * FROM t1;
SELECT * FROM t1 WHERE d1 IS NULL;
EXPLAIN EXTENDED SELECT * FROM t1 WHERE d1 IS NULL;
SELECT count(*) FROM t1 WHERE d1 IS NULL;
CREATE VIEW v1 AS (SELECT * FROM t1);
SELECT * FROM v1;
SELECT * FROM v1 WHERE d1 IS NULL;
EXPLAIN EXTENDED SELECT * FROM v1 WHERE d1 IS NULL;
SELECT count(*) FROM v1 WHERE d1 IS NULL;
SET @save_optimizer_switch=@@optimizer_switch;
SET SESSION optimizer_switch='derived_merge=off';
SELECT count(*) FROM ( SELECT * FROM t1 ) AS a1 WHERE d1 IS NULL;
SET SESSION optimizer_switch='derived_merge=on';
SELECT count(*) FROM ( SELECT * FROM t1 ) AS a1 WHERE d1 IS NULL;
SET optimizer_switch=@save_optimizer_switch;
CREATE TABLE t2 (d1 datetime NOT NULL);
INSERT INTO t2 VALUES
('1980-09-03 20:49:36'), ('0000-00-00 00:00:00'), ('1979-09-03 20:49:36');
SELECT * FROM t2 LEFT JOIN t1 ON t2.d1=t1.d1 WHERE t1.d1 IS NULL;
EXPLAIN EXTENDED
SELECT * FROM t2 LEFT JOIN t1 ON t2.d1=t1.d1 WHERE t1.d1 IS NULL;
SELECT * FROM t2 LEFT JOIN v1 ON t2.d1=v1.d1 WHERE v1.d1 IS NULL;
EXPLAIN EXTENDED
SELECT * FROM t2 LEFT JOIN v1 ON t2.d1=v1.d1 WHERE v1.d1 IS NULL;
DROP VIEW v1;
DROP TABLE t1,t2;
--echo #
--echo # End of 5.5 tests
--echo #

8
sql/sql_select.cc
View File

@ -13980,9 +13980,9 @@ bool cond_is_datetime_is_null(Item *cond)
((Item_func*) cond)->functype() == Item_func::ISNULL_FUNC)
{
Item **args= ((Item_func_isnull*) cond)->arguments();
if (args[0]->type() == Item::FIELD_ITEM)
if (args[0]->real_item()->type() == Item::FIELD_ITEM)
{
Field *field=((Item_field*) args[0])->field;
Field *field=((Item_field*) (args[0]->real_item()))->field;
if (((field->type() == MYSQL_TYPE_DATE) ||
(field->type() == MYSQL_TYPE_DATETIME)) &&
@ -14308,14 +14308,14 @@ internal_remove_eq_conds(THD *thd, COND *cond, Item::cond_result *cond_value)
*/
Item **args= ((Item_func_isnull*) cond)->arguments();
Field *field=((Item_field*) args[0])->field;
Field *field=((Item_field*) (args[0]->real_item()))->field;
Item *item0= new(thd->mem_root) Item_int((longlong)0, 1);
Item *eq_cond= new(thd->mem_root) Item_func_eq(args[0], item0);
if (!eq_cond)
return cond;
if (field->table->pos_in_table_list->is_inner_table_of_outer_join())
if (field->table->pos_in_table_list->is_inner_table_of_outer_join())
{
// outer join: transform "col IS NULL" to "col IS NULL or col=0"
Item *or_cond= new(thd->mem_root) Item_cond_or(eq_cond, cond);