mariadb/mysql-test/r/null_key.result

drop table if exists t1;
create table t1 (a int, b int not null,unique key (a,b),index(b)) type=myisam;
insert ignore into t1 values (1,1),(2,2),(3,3),(4,4),(5,5),(6,6),(null,7),(9,9),(8,8),(7,7),(null,9),(null,9),(6,6);
explain select * from t1 where a is null;
table	type	possible_keys	key	key_len	ref	rows	Extra
t1	ref	a	a	5	const	3	where used; Using index
explain select * from t1 where a is null and b = 2;
table	type	possible_keys	key	key_len	ref	rows	Extra
t1	ref	a,b	a	9	const,const	1	where used; Using index
explain select * from t1 where a is null and b = 7;
table	type	possible_keys	key	key_len	ref	rows	Extra
t1	ref	a,b	a	9	const,const	1	where used; Using index
explain select * from t1 where a=2 and b = 2;
table	type	possible_keys	key	key_len	ref	rows	Extra
t1	const	a,b	a	9	const,const	1	
explain select * from t1 where a<=>b limit 2;
table	type	possible_keys	key	key_len	ref	rows	Extra
t1	index	NULL	a	9	NULL	12	where used; Using index
explain select * from t1 where (a is null or a > 0 and a < 3) and b < 5 limit 3;
table	type	possible_keys	key	key_len	ref	rows	Extra
t1	range	a,b	a	9	NULL	3	where used; Using index
explain select * from t1 where (a is null or a = 7) and b=7;
table	type	possible_keys	key	key_len	ref	rows	Extra
t1	range	a,b	a	9	NULL	2	where used; Using index
explain select * from t1 where (a is null and b>a) or a is null and b=7 limit 2;
table	type	possible_keys	key	key_len	ref	rows	Extra
t1	ref	a,b	a	5	const	3	where used; Using index
explain select * from t1 where a is null and b=9 or a is null and b=7 limit 3;
table	type	possible_keys	key	key_len	ref	rows	Extra
t1	range	a,b	a	9	NULL	2	where used; Using index
explain select * from t1 where a > 1 and a < 3 limit 1;
table	type	possible_keys	key	key_len	ref	rows	Extra
t1	range	a	a	5	NULL	1	where used; Using index
explain select * from t1 where a > 8 and a < 9;
table	type	possible_keys	key	key_len	ref	rows	Extra
t1	range	a	a	5	NULL	1	where used; Using index
select * from t1 where a is null;
a	b
NULL	7
NULL	9
NULL	9
select * from t1 where a is null and b = 7;
a	b
NULL	7
select * from t1 where a<=>b limit 2;
a	b
1	1
2	2
select * from t1 where (a is null or a > 0 and a < 3) and b < 5 limit 3;
a	b
1	1
2	2
select * from t1 where (a is null or a > 0 and a < 3) and b > 7 limit 3;
a	b
NULL	9
NULL	9
select * from t1 where (a is null or a = 7) and b=7;
a	b
NULL	7
7	7
select * from t1 where a is null and b=9 or a is null and b=7 limit 3;
a	b
NULL	7
NULL	9
NULL	9
alter table t1 modify b blob not null, add c int not null, drop key a, add unique key (a,b(20),c), drop key b, add key (b(10));
explain select * from t1 where a is null and b = 2;
table	type	possible_keys	key	key_len	ref	rows	Extra
t1	ref	a,b	a	5	const	3	where used
explain select * from t1 where a is null and b = 2 and c=0;
table	type	possible_keys	key	key_len	ref	rows	Extra
t1	ref	a,b	a	5	const	3	where used
explain select * from t1 where a is null and b = 7 and c=0;
table	type	possible_keys	key	key_len	ref	rows	Extra
t1	ref	a,b	a	5	const	3	where used
explain select * from t1 where a=2 and b = 2;
table	type	possible_keys	key	key_len	ref	rows	Extra
t1	ref	a,b	a	5	const	1	where used
explain select * from t1 where a<=>b limit 2;
table	type	possible_keys	key	key_len	ref	rows	Extra
t1	ALL	NULL	NULL	NULL	NULL	12	where used
explain select * from t1 where (a is null or a > 0 and a < 3) and b < 5 and c=0 limit 3;
table	type	possible_keys	key	key_len	ref	rows	Extra
t1	range	a,b	a	5	NULL	5	where used
explain select * from t1 where (a is null or a = 7) and b=7 and c=0;
table	type	possible_keys	key	key_len	ref	rows	Extra
t1	range	a,b	a	5	NULL	4	where used
explain select * from t1 where (a is null and b>a) or a is null and b=7 limit 2;
table	type	possible_keys	key	key_len	ref	rows	Extra
t1	ref	a,b	a	5	const	3	where used
explain select * from t1 where a is null and b=9 or a is null and b=7 limit 3;
table	type	possible_keys	key	key_len	ref	rows	Extra
t1	ref	a,b	a	5	const	3	where used
explain select * from t1 where a > 1 and a < 3 limit 1;
table	type	possible_keys	key	key_len	ref	rows	Extra
t1	range	a	a	5	NULL	1	where used
explain select * from t1 where a is null and b=7 or a > 1 and a < 3 limit 1;
table	type	possible_keys	key	key_len	ref	rows	Extra
t1	range	a,b	a	5	NULL	4	where used
explain select * from t1 where a > 8 and a < 9;
table	type	possible_keys	key	key_len	ref	rows	Extra
t1	range	a	a	5	NULL	1	where used
explain select * from t1 where b like "6%";
table	type	possible_keys	key	key_len	ref	rows	Extra
t1	range	b	b	12	NULL	1	where used
select * from t1 where a is null;
a	b	c
NULL	7	0
NULL	9	0
NULL	9	0
select * from t1 where a is null and b = 7 and c=0;
a	b	c
NULL	7	0
select * from t1 where a<=>b limit 2;
a	b	c
1	1	0
2	2	0
select * from t1 where (a is null or a > 0 and a < 3) and b < 5 limit 3;
a	b	c
1	1	0
2	2	0
select * from t1 where (a is null or a > 0 and a < 3) and b > 7 limit 3;
a	b	c
NULL	9	0
NULL	9	0
select * from t1 where (a is null or a = 7) and b=7 and c=0;
a	b	c
NULL	7	0
7	7	0
select * from t1 where a is null and b=9 or a is null and b=7 limit 3;
a	b	c
NULL	7	0
NULL	9	0
NULL	9	0
select * from t1 where b like "6%";
a	b	c
6	6	0
drop table t1;
DROP TABLE IF EXISTS t1,t2;
CREATE TABLE t1 (
id int(10) unsigned NOT NULL auto_increment,
uniq_id int(10) unsigned default NULL,
PRIMARY KEY  (id),
UNIQUE KEY idx1 (uniq_id)
) TYPE=MyISAM;
CREATE TABLE t2 (
id int(10) unsigned NOT NULL auto_increment,
uniq_id int(10) unsigned default NULL,
PRIMARY KEY  (id)
) TYPE=MyISAM;
INSERT INTO t1 VALUES (1,NULL),(2,NULL),(3,1),(4,2),(5,NULL),(6,NULL),(7,3),(8,4),(9,NULL),(10,NULL);
INSERT INTO t2 VALUES (1,NULL),(2,NULL),(3,1),(4,2),(5,NULL),(6,NULL),(7,3),(8,4),(9,NULL),(10,NULL);
explain select id from t1 where uniq_id is null;
table	type	possible_keys	key	key_len	ref	rows	Extra
t1	ref	idx1	idx1	5	const	1	where used
explain select id from t1 where uniq_id =1;
table	type	possible_keys	key	key_len	ref	rows	Extra
t1	const	idx1	idx1	5	const	1	
UPDATE t1 SET id=id+100 where uniq_id is null;
UPDATE t2 SET id=id+100 where uniq_id is null;
select id from t1 where uniq_id is null;
id
101
102
105
106
109
110
select id from t2 where uniq_id is null;
id
101
102
105
106
109
110
DELETE FROM t1 WHERE uniq_id IS NULL;
DELETE FROM t2 WHERE uniq_id IS NULL;
SELECT * FROM t1 ORDER BY uniq_id, id;
id	uniq_id
3	1
4	2
7	3
8	4
SELECT * FROM t2 ORDER BY uniq_id, id;
id	uniq_id
3	1
4	2
7	3
8	4
DROP table t1,t2;