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drop table if exists t1,t2,t3;
select * from (select 2 from DUAL) b;
2
2
SELECT 1 as a FROM (SELECT 1 UNION SELECT a) b;
ERROR 42S22: Unknown column 'a' in 'field list'
SELECT 1 as a FROM (SELECT a UNION SELECT 1) b;
ERROR 42S22: Unknown column 'a' in 'field list'
CREATE TABLE t1 (a int not null, b char (10) not null);
insert into t1 values(1,'a'),(2,'b'),(3,'c'),(3,'c');
CREATE TABLE t2 (a int not null, b char (10) not null);
insert into t2 values (3,'c'),(4,'d'),(5,'f'),(6,'e');
select t1.a,t3.y from t1,(select a as y from t2 where b='c') as t3 where t1.a = t3.y;
a y
3 3
3 3
select t1.a,t3.a from t1,(select * from t2 where b='c') as t3 where t1.a = t3.a;
a a
3 3
3 3
CREATE TABLE t3 (a int not null, b char (10) not null);
insert into t3 values (3,'f'),(4,'y'),(5,'z'),(6,'c');
select t1.a,t4.y from t1,(select t2.a as y from t2,(select t3.b from t3 where t3.a>3) as t5 where t2.b=t5.b) as t4 where t1.a = t4.y;
a y
3 3
3 3
SELECT a FROM (SELECT 1 FROM (SELECT 1) a HAVING a=1) b;
ERROR 42S22: Unknown column 'a' in 'having clause'
SELECT a,b as a FROM (SELECT '1' as a,'2' as b) b HAVING a=1;
ERROR 23000: Column: 'a' in having clause is ambiguous
SELECT a,2 as a FROM (SELECT '1' as a) b HAVING a=2;
a a
1 2
SELECT a,2 as a FROM (SELECT '1' as a) b HAVING a=1;
a a
SELECT 1 FROM (SELECT 1) a WHERE a=2;
ERROR 42S22: Unknown column 'a' in 'where clause'
SELECT (SELECT 1) as a FROM (SELECT 1 FROM t1 HAVING a=1) as a;
ERROR 42S22: Unknown column 'a' in 'having clause'
select * from t1 as x1, (select * from t1) as x2;
a b a b
1 a 1 a
2 b 1 a
3 c 1 a
3 c 1 a
1 a 2 b
2 b 2 b
3 c 2 b
3 c 2 b
1 a 3 c
2 b 3 c
3 c 3 c
3 c 3 c
1 a 3 c
2 b 3 c
3 c 3 c
3 c 3 c
explain select * from t1 as x1, (select * from t1) as x2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY x1 ALL NULL NULL NULL NULL 4
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 4
2 DERIVED x1 ALL NULL NULL NULL NULL 4
drop table if exists t2,t3;
select * from (select 1) as a;
1
1
select a from (select 1 as a) as b;
a
1
select 1 from (select 1) as a;
1
1
select * from (select * from t1 union select * from t1) a;
a b
1 a
2 b
3 c
select * from (select * from t1 union all select * from t1) a;
a b
1 a
2 b
3 c
3 c
1 a
2 b
3 c
3 c
explain select * from (select * from t1 union select * from t1) a;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 3
2 DERIVED t1 ALL NULL NULL NULL NULL 4
3 UNION t1 ALL NULL NULL NULL NULL 4
explain select * from (select * from t1 union all select * from t1) a;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 8
2 DERIVED t1 ALL NULL NULL NULL NULL 4
3 UNION t1 ALL NULL NULL NULL NULL 4
CREATE TABLE t2 (a int not null);
insert into t2 values(1);
select * from (select * from t1 where t1.a=(select a from t2 where t2.a=t1.a)) a;
a b
1 a
select * from (select * from t1 where t1.a=(select t2.a from t2 where t2.a=t1.a) union select t1.a, t1.b from t1) a;
a b
1 a
2 b
3 c
explain select * from (select * from t1,t2 where t1.a=t2.a) t1;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY <derived2> system NULL NULL NULL NULL 1
2 DERIVED t2 system NULL NULL NULL NULL 1
2 DERIVED t1 ALL NULL NULL NULL NULL 4 Using where
drop table t1, t2;
create table t1(a int not null, t char(8), index(a));
SELECT * FROM (SELECT * FROM t1) as b ORDER BY a ASC LIMIT 0,20;
a t
1 1
2 2
3 3
4 4
5 5
6 6
7 7
8 8
9 9
10 10
11 11
12 12
13 13
14 14
15 15
16 16
17 17
18 18
19 19
20 20
explain select count(*) from t1 as tt1, (select * from t1) as tt2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
2 DERIVED tt1 ALL NULL NULL NULL NULL 10000
drop table t1;
SELECT * FROM (SELECT (SELECT * FROM (SELECT 1 as a) as a )) as b;
(SELECT * FROM (SELECT 1 as a) as a )
1
select * from (select 1 as a) b left join (select 2 as a) c using(a);
a a
1 NULL
SELECT * FROM (SELECT 1 UNION SELECT a) b;
ERROR 42S22: Unknown column 'a' in 'field list'
SELECT 1 as a FROM (SELECT a UNION SELECT 1) b;
ERROR 42S22: Unknown column 'a' in 'field list'
SELECT 1 as a FROM (SELECT 1 UNION SELECT a) b;
ERROR 42S22: Unknown column 'a' in 'field list'
select 1 from (select 2) a order by 0;
ERROR 42S22: Unknown column '0' in 'order clause'
create table t1 (id int);
insert into t1 values (1),(2),(3);
describe select * from (select * from t1 group by id) bar;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 3
2 DERIVED t1 ALL NULL NULL NULL NULL 3 Using temporary; Using filesort
drop table t1;
create table t1 (mat_id MEDIUMINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY, matintnum CHAR(6) NOT NULL, test MEDIUMINT UNSIGNED NULL);
create table t2 (mat_id MEDIUMINT UNSIGNED NOT NULL, pla_id MEDIUMINT UNSIGNED NOT NULL);
insert into t1 values (NULL, 'a', 1), (NULL, 'b', 2), (NULL, 'c', 3), (NULL, 'd', 4), (NULL, 'e', 5), (NULL, 'f', 6), (NULL, 'g', 7), (NULL, 'h', 8), (NULL, 'i', 9);
insert into t2 values (1, 100), (1, 101), (1, 102), (2, 100), (2, 103), (2, 104), (3, 101), (3, 102), (3, 105);
SELECT STRAIGHT_JOIN d.pla_id, m2.mat_id FROM t1 m2 INNER JOIN (SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id GROUP BY mp.pla_id) d ON d.matintnum=m2.matintnum;
pla_id mat_id
100 1
101 1
102 1
103 2
104 2
105 3
SELECT STRAIGHT_JOIN d.pla_id, m2.test FROM t1 m2 INNER JOIN (SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id GROUP BY mp.pla_id) d ON d.matintnum=m2.matintnum;
pla_id test
100 1
101 1
102 1
103 2
104 2
105 3
explain SELECT STRAIGHT_JOIN d.pla_id, m2.mat_id FROM t1 m2 INNER JOIN (SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id GROUP BY mp.pla_id) d ON d.matintnum=m2.matintnum;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY m2 ALL NULL NULL NULL NULL 9
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 6 Using where
2 DERIVED mp ALL NULL NULL NULL NULL 9 Using temporary; Using filesort
2 DERIVED m2 index NULL PRIMARY 3 NULL 9 Using index
explain SELECT STRAIGHT_JOIN d.pla_id, m2.test FROM t1 m2 INNER JOIN (SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id GROUP BY mp.pla_id) d ON d.matintnum=m2.matintnum;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY m2 ALL NULL NULL NULL NULL 9
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 6 Using where
2 DERIVED mp ALL NULL NULL NULL NULL 9 Using temporary; Using filesort
2 DERIVED m2 index NULL PRIMARY 3 NULL 9 Using index
drop table t1,t2;
SELECT a.x FROM (SELECT 1 AS x) AS a HAVING a.x = 1;
x
1
create table t1 select 1 as a;
select 2 as a from (select * from t1) b;
ERROR 3D000: No Database Selected
use test;
select 2 as a from (select * from t1) b;
a
2
drop table t1;
select mail_id, if(folder.f_description!='', folder.f_description, folder.f_name) as folder_name, date, address_id, phrase, address, subject from folder, (select mail.mail_id as mail_id, date_format(mail.h_date, '%b %e, %Y %h:%i') as date, mail.folder_id, sender.address_id as address_id, sender.phrase as phrase, sender.address as address, mail.h_subject as subject from mail left join mxa as mxa_sender on mail.mail_id=mxa_sender.mail_id and mxa_sender.type='from' left join address as sender on mxa_sender.address_id=sender.address_id mxa as mxa_recipient, address as recipient, where 1 and mail.mail_id=mxa_recipient.mail_id and mxa_recipient.address_id=recipient.address_id and mxa_recipient.type='to' and match(sender.phrase, sender.address, sender.comment) against ('jeremy' in boolean mode) and match(recipient.phrase, recipient.address, recipient.comment) against ('monty' in boolean mode) order by mail.h_date desc limit 0, 25 ) as query where query.folder_id=folder.folder_id;
ERROR 42000: You have an error in your SQL syntax. Check the manual that corresponds to your MySQL server version for the right syntax to use near 'mxa as mxa_recipient, address as recipient, where 1 and mail.mail_id=mxa_r' at line 1
create table t1 (a int);
insert into t1 values (1),(2),(3);
update (select * from t1) as t1 set a = 5;
ERROR 42000: You have an error in your SQL syntax. Check the manual that corresponds to your MySQL server version for the right syntax to use
delete from (select * from t1);
ERROR 42000: You have an error in your SQL syntax. Check the manual that corresponds to your MySQL server version for the right syntax to use near '(select * from t1)' at line 1
insert into (select * from t1) values (5);
ERROR 42000: You have an error in your SQL syntax. Check the manual that corresponds to your MySQL server version for the right syntax to use near '(select * from t1) values (5)' at line 1
drop table t1;
create table t1 (E1 INTEGER UNSIGNED NOT NULL, E2 INTEGER UNSIGNED NOT NULL, E3 INTEGER UNSIGNED NOT NULL, PRIMARY KEY(E1)
);
insert into t1 VALUES(1,1,1), (2,2,1);
select count(*) from t1 INNER JOIN (SELECT A.E1, A.E2, A.E3 FROM t1 AS A WHERE A.E3 = (SELECT MAX(B.E3) FROM t1 AS B WHERE A.E2 = B.E2)) AS THEMAX ON t1.E1 = THEMAX.E2 AND t1.E1 = t1.E2;
count(*)
2
explain select count(*) from t1 INNER JOIN (SELECT A.E1, A.E2, A.E3 FROM t1 AS A WHERE A.E3 = (SELECT MAX(B.E3) FROM t1 AS B WHERE A.E2 = B.E2)) AS THEMAX ON t1.E1 = THEMAX.E2 AND t1.E1 = t1.E2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 2
1 PRIMARY t1 eq_ref PRIMARY PRIMARY 4 THEMAX.E2 1 Using where
2 DERIVED t1 ALL NULL NULL NULL NULL 2 Using where
3 DEPENDENT SUBQUERY B ALL NULL NULL NULL NULL 2 Using where
drop table t1;
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