mariadb/mysql-test/r/subselect.result

select (select 2);
(select 2)
2
drop table if exists t1,t2,t3,t4,t5,attend,clinic,inscrit;
create table t1 (a int);
create table t2 (a int, b int);
create table t3 (a int);
create table t4 (a int, b int);
insert into t1 values (2);
insert into t2 values (1,7),(2,7);
insert into t4 values (4,8),(3,8),(5,9);
select (select a from t1 where t1.a=t2.a), a from t2;
(select a from t1 where t1.a=t2.a)	a
NULL	1
2	2
select (select a from t1 where t1.a=t2.b), a from t2;
(select a from t1 where t1.a=t2.b)	a
NULL	1
NULL	2
select (select a from t1), a from t2;
(select a from t1)	a
2	1
2	2
select (select a from t3), a from t2;
(select a from t3)	a
NULL	1
NULL	2
select * from t2 where t2.a=(select a from t1);
a	b
2	7
insert into t3 values (6),(7),(3);
select * from t2 where t2.b=(select a from t3 order by 1 desc limit 1);
a	b
1	7
2	7
select * from t2 where t2.b=(select a from t3 order by 1 desc limit 1) 
union (select * from t4 order by a limit 2) limit 3;
a	b
1	7
2	7
3	8
select * from t2 where t2.b=(select a from t3 order by 1 desc limit 1) 
union (select * from t4 where t4.b=(select max(t2.a)*4 from t2) order by a);
a	b
1	7
2	7
3	8
4	8
explain select * from t2 where t2.b=(select a from t3 order by 1 desc limit 1) 
union (select * from t4 where t4.b=(select max(t2.a)*4 from t2) order by a);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	where used
3	UNION	t4	ALL	NULL	NULL	NULL	NULL	3	where used; Using filesort
4	SUBSELECT	t2	ALL	NULL	NULL	NULL	NULL	2	
2	SUBSELECT	t3	ALL	NULL	NULL	NULL	NULL	3	Using filesort
select (select a from t3 where a<t2.a*4 order by 1 desc limit 1), a from t2;
(select a from t3 where a<t2.a*4 order by 1 desc limit 1)	a
3	1
7	2
select (select t3.a from t3 where a<8 order by 1 desc limit 1), a from 
(select * from t2 where a>1) as tt;
(select t3.a from t3 where a<8 order by 1 desc limit 1)	a
7	2
explain select (select t3.a from t3 where a<8 order by 1 desc limit 1), a from 
(select * from t2 where a>1) as tt;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
3	DERIVED	t2	ALL	NULL	NULL	NULL	NULL	2	where used
1	PRIMARY	<derived3>	system	NULL	NULL	NULL	NULL	1	
2	SUBSELECT	t3	ALL	NULL	NULL	NULL	NULL	3	where used; Using filesort
select * from t1 where t1.a=(select t2.a from t2 where t2.b=(select max(a) from t3) order by 1 desc limit 1);
a
2
select * from t1 where t1.a=(select t2.a from t2 where t2.b=(select max(a) from t3 where t3.a > t1.a) order by 1 desc limit 1);
a
2
select * from t1 where t1.a=(select t2.a from t2 where t2.b=(select max(a) from t3 where t3.a < t1.a) order by 1 desc limit 1);
a
select b,(select avg(t2.a+(select min(t3.a) from t3 where t3.a >= t4.a)) from t2) from t4;
b	(select avg(t2.a+(select min(t3.a) from t3 where t3.a >= t4.a)) from t2)
8	7.5000
8	4.5000
9	7.5000
explain select b,(select avg(t2.a+(select min(t3.a) from t3 where t3.a >= t4.a)) from t2) from t4;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t4	ALL	NULL	NULL	NULL	NULL	3	
2	DEPENDENT SUBSELECT	t2	ALL	NULL	NULL	NULL	NULL	2	
3	DEPENDENT SUBSELECT	t3	ALL	NULL	NULL	NULL	NULL	3	where used
select * from t3 where exists (select * from t2 where t2.b=t3.a);
a
7
select * from t3 where not exists (select * from t2 where t2.b=t3.a);
a
6
3
insert into t4 values (12,7),(1,7),(10,9),(9,6),(7,6),(3,9);
select b,max(a) as ma from t4 group by b having b < (select max(t2.a)
from t2 where t2.b=t4.b);
b	ma
select b,max(a) as ma from t4 group by b having b >= (select max(t2.a)
from t2 where t2.b=t4.b);
b	ma
7	12
create table t5 (a int);
select (select a from t1 where t1.a=t2.a union select a from t5 where t5.a=t2.a), a from t2;
(select a from t1 where t1.a=t2.a union select a from t5 where t5.a=t2.a)	a
NULL	1
2	2
insert into t5 values (5);
select (select a from t1 where t1.a=t2.a union select a from t5 where t5.a=t2.a), a from t2;
(select a from t1 where t1.a=t2.a union select a from t5 where t5.a=t2.a)	a
NULL	1
2	2
insert into t5 values (2);
select (select a from t1 where t1.a=t2.a union select a from t5 where t5.a=t2.a), a from t2;
(select a from t1 where t1.a=t2.a union select a from t5 where t5.a=t2.a)	a
NULL	1
2	2
explain select (select a from t1 where t1.a=t2.a union select a from t5 where t5.a=t2.a), a from t2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	
2	DEPENDENT SUBSELECT	t1	system	NULL	NULL	NULL	NULL	1	where used
3	DEPENDENT UNION	t5	ALL	NULL	NULL	NULL	NULL	2	where used
select (select a from t1 where t1.a=t2.a union all select a from t5 where t5.a=t2.a), a from t2;
Subselect returns more than 1 record
create table attend (patient_uq int, clinic_uq int, index i1 (clinic_uq));
create table clinic( uq int primary key, name char(25));
insert into clinic values(1,"Oblastnaia bolnitsa"),(2,"Bolnitsa Krasnogo Kresta");
insert into attend values (1,1),(1,2),(2,2),(1,3);
select * from attend where exists (select * from clinic where uq = clinic_uq);
patient_uq	clinic_uq
1	1
1	2
2	2
drop table if exists t1,t2,t3;
CREATE TABLE t3 (a varchar(20),b char(1) NOT NULL default '0');
INSERT INTO t3 VALUES ('W','a'),('A','c'),('J','b');
CREATE TABLE t2 (a varchar(20),b int NOT NULL default '0');
INSERT INTO t2 VALUES ('W','1'),('A','3'),('J','2');
CREATE TABLE t1 (a varchar(20),b date NOT NULL default '0000-00-00');
INSERT INTO t1 VALUES ('W','1732-02-22'),('A','1735-10-30'),('J','1743-04-13');
SELECT * FROM t1 WHERE b = (SELECT MIN(b) FROM t1);
a	b
W	1732-02-22
SELECT * FROM t2 WHERE b = (SELECT MIN(b) FROM t2);
a	b
W	1
SELECT * FROM t3 WHERE b = (SELECT MIN(b) FROM t3);
a	b
W	a
drop table if exists inscrit;
CREATE TABLE `inscrit` (
`pseudo` varchar(35) character set latin1 NOT NULL default '',
`email` varchar(60) character set latin1 NOT NULL default '',
PRIMARY KEY  (`pseudo`),
UNIQUE KEY `email` (`email`)
) TYPE=MyISAM CHARSET=latin1 ROW_FORMAT=DYNAMIC;
INSERT INTO inscrit (pseudo,email) VALUES ('joce','test');
INSERT INTO inscrit (pseudo,email) VALUES ('joce1','test1');
INSERT INTO inscrit (pseudo,email) VALUES ('2joce1','2test1');
SELECT pseudo FROM inscrit WHERE pseudo=(SELECT pseudo FROM inscrit WHERE pseudo LIKE '%joce%');
Subselect returns more than 1 record
drop table if exists inscrit;