~drizzle-trunk/drizzle/development

drop table if exists t1,t2,t3;
SET SQL_WARNINGS=1;
CREATE TABLE t1 (
ID CHAR(32) NOT NULL,
name CHAR(32) NOT NULL,
value CHAR(255),
INDEX indexIDname (ID(8),name(8))
) ;
INSERT INTO t1 VALUES
('keyword','indexdir','/export/home/local/www/database/indexes/keyword');
INSERT INTO t1 VALUES ('keyword','urlprefix','text/ /text');
INSERT INTO t1 VALUES ('keyword','urlmap','/text/ /');
INSERT INTO t1 VALUES ('keyword','attr','personal employee company');
INSERT INTO t1 VALUES
('emailgids','indexdir','/export/home/local/www/database/indexes/emailgids');
INSERT INTO t1 VALUES ('emailgids','urlprefix','text/ /text');
INSERT INTO t1 VALUES ('emailgids','urlmap','/text/ /');
INSERT INTO t1 VALUES ('emailgids','attr','personal employee company');
SELECT value FROM t1 WHERE ID='emailgids' AND name='attr';
value
personal employee company
drop table t1;
CREATE TABLE t1 (
price int DEFAULT '0' NOT NULL,
area varchar(160) DEFAULT '' NOT NULL,
type varchar(160) DEFAULT '' NOT NULL,
transityes enum('Y','N') DEFAULT 'Y' NOT NULL,
shopsyes enum('Y','N') DEFAULT 'Y' NOT NULL,
schoolsyes enum('Y','N') DEFAULT 'Y' NOT NULL,
petsyes enum('Y','N') DEFAULT 'Y' NOT NULL,
KEY price (price,area,type,transityes,shopsyes,schoolsyes,petsyes)
);
INSERT INTO t1 VALUES (900,'Vancouver','Shared/Roomate','N','N','N','N');
INSERT INTO t1 VALUES (900,'Vancouver','Shared/Roomate','N','N','N','N');
INSERT INTO t1 (price, area, type) VALUES (900,'Vancouver','Shared/Roomate');
INSERT INTO t1 VALUES (900,'Vancouver','Shared/Roomate','Y','Y','Y','Y');
INSERT INTO t1 VALUES (900,'Vancouver','Shared/Roomate','Y','Y','Y','Y');
INSERT INTO t1 VALUES (900,'Vancouver','Shared/Roomate','Y','Y','Y','Y');
INSERT INTO t1 VALUES (900,'Vancouver','Shared/Roomate','Y','Y','Y','Y');
INSERT INTO t1 VALUES (900,'Vancouver','Shared/Roomate','Y','Y','Y','Y');
SELECT * FROM t1 WHERE area='Vancouver' and transityes='y' and schoolsyes='y' and ( ((type='1 Bedroom' or type='Studio/Bach') and (price<=500)) or ((type='2 Bedroom') and (price<=550)) or ((type='Shared/Roomate') and (price<=300)) or ((type='Room and Board') and (price<=500)) ) and price <= 400;
price	area	type	transityes	shopsyes	schoolsyes	petsyes
drop table t1;
CREATE TABLE t1 (program enum('signup','unique','sliding') not null,  type enum('basic','sliding','signup'),  PRIMARY KEY (program));
ALTER TABLE t1 modify program enum('signup','unique','sliding');
drop table t1;
CREATE TABLE t1 (
name varchar(50) DEFAULT '' NOT NULL,
author varchar(50) DEFAULT '' NOT NULL,
category decimal(10,0) DEFAULT '0' NOT NULL,
email varchar(50),
password varchar(50),
proxy varchar(50),
bitmap varchar(20),
msg varchar(255),
urlscol varchar(127),
urlhttp varchar(127),
timeout decimal(10,0),
nbcnx decimal(10,0),
creation decimal(10,0),
livinguntil decimal(10,0),
lang decimal(10,0),
type decimal(10,0),
subcat decimal(10,0),
subtype decimal(10,0),
reg char(1),
scs varchar(255),
capacity decimal(10,0),
userISP varchar(50),
CCident varchar(50) DEFAULT '' NOT NULL,
PRIMARY KEY (name,author,category)
);
INSERT INTO t1 VALUES
('patnom','patauteur',0,'p.favre@cryo-networks.fr',NULL,NULL,'#p2sndnq6ae5g1u6t','essai salut','scol://195.242.78.119:patauteur.patnom',NULL,NULL,NULL,950036174,-882087474,NULL,3,0,3,'1','Pub/patnom/futur_divers.scs',NULL,'pat','CC1');
INSERT INTO t1 VALUES
('LeNomDeMonSite','Marc',0,'m.barilley@cryo-networks.fr',NULL,NULL,NULL,NULL,'scol://195.242.78.119:Marc.LeNomDeMonSite',NULL,NULL,NULL,950560434,-881563214,NULL,3,0,3,'1','Pub/LeNomDeMonSite/domus_hibere.scs',NULL,'Marq','CC1');
select * from t1 where name='patnom' and author='patauteur' and category=0;
name	author	category	email	password	proxy	bitmap	msg	urlscol	urlhttp	timeout	nbcnx	creation	livinguntil	lang	type	subcat	subtype	reg	scs	capacity	userISP	CCident
patnom	patauteur	0	p.favre@cryo-networks.fr	NULL	NULL	#p2sndnq6ae5g1u6t	essai salut	scol://195.242.78.119:patauteur.patnom	NULL	NULL	NULL	950036174	-882087474	NULL	3	0	3	1	Pub/patnom/futur_divers.scs	NULL	pat	CC1
drop table t1;
create table t1
(
name_id int not null auto_increment,
name blob,
INDEX name_idx (name(5)),
primary key (name_id)
);
INSERT t1 VALUES(NULL,'/');
INSERT t1 VALUES(NULL,'[T,U]_axpby');
SELECT * FROM t1 WHERE name='[T,U]_axpy';
name_id	name
SELECT * FROM t1 WHERE name='[T,U]_axpby';
name_id	name
2	[T,U]_axpby
create table t2
(
name_id int not null auto_increment,
name char(255) binary,
INDEX name_idx (name(5)),
primary key (name_id)
);
INSERT t2 select * from t1;
SELECT * FROM t2 WHERE name='[T,U]_axpy';
name_id	name
SELECT * FROM t2 WHERE name='[T,U]_axpby';
name_id	name
2	[T,U]_axpby
CREATE TABLE t3 SELECT * FROM t2 WHERE name='[T,U]_axpby';
SELECT * FROM t2 WHERE name='[T,U]_axpby';
name_id	name
2	[T,U]_axpby
drop table t1,t2,t3;
create table t1
(
SEQNO                         numeric(12 ) not null,
MOTYPEID                 numeric(12 ) not null,
MOINSTANCEID     numeric(12 ) not null,
ATTRID                       numeric(12 ) not null,
VALUE                         varchar(120) not null,
primary key (SEQNO, MOTYPEID, MOINSTANCEID, ATTRID, VALUE )
);
INSERT INTO t1 VALUES (1, 1, 1, 1, 'a');
INSERT INTO t1 VALUES (1, 1, 1, 1, 'b');
INSERT INTO t1 VALUES (1, 1, 1, 1, 'a');
ERROR 23000: Duplicate entry '1-1-1-1-a' for key 'PRIMARY'
drop table t1;
CREATE TABLE t1 (
a tinytext NOT NULL,
b int NOT NULL default '0',
PRIMARY KEY (a(32),b)
) ENGINE=MyISAM;
INSERT INTO t1 VALUES ('a',1),('a',2);
SELECT * FROM t1 WHERE a='a' AND b=2;
a	b
a	2
SELECT * FROM t1 WHERE a='a' AND b in (2);
a	b
a	2
SELECT * FROM t1 WHERE a='a' AND b in (1,2);
a	b
a	1
a	2
drop table t1;
create table t1 (a int not null unique, b int unique, c int, d int not null primary key, key(c), e int not null unique);
show keys from t1;
Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_Comment
t1	0	PRIMARY	1	d	A	0	NULL	NULL		BTREE		
t1	0	a	1	a	A	0	NULL	NULL		BTREE		
t1	0	e	1	e	A	0	NULL	NULL		BTREE		
t1	0	b	1	b	A	0	NULL	NULL	YES	BTREE		
t1	1	c	1	c	A	0	NULL	NULL	YES	BTREE		
drop table t1;
CREATE TABLE t1 (c VARCHAR(10) NOT NULL,i INT PRIMARY KEY NOT NULL AUTO_INCREMENT, UNIQUE (c,i));
INSERT INTO t1 (c) VALUES (NULL),(NULL);
ERROR 23000: Column 'c' cannot be null
SELECT * FROM t1;
c	i
INSERT INTO t1 (c) VALUES ('a'),('a');
SELECT * FROM t1;
c	i
a	1
a	2
DROP TABLE IF EXISTS t1;
CREATE TABLE t1 (c CHAR(10) NULL, i INT PRIMARY KEY NOT NULL AUTO_INCREMENT, UNIQUE (c,i));
INSERT INTO t1 (c) VALUES (NULL),(NULL);
SELECT * FROM t1;
c	i
NULL	1
NULL	2
INSERT INTO t1 (c) VALUES ('a'),('a');
SELECT * FROM t1;
c	i
NULL	1
NULL	2
a	3
a	4
drop table t1;
CREATE TABLE t1 (id int auto_increment, name char(50), primary key (id)) engine=myisam;
insert into t1 (name) values ('a'), ('b'),('c'),('d'),('e'),('f'),('g');
explain select 1 from t1 where id =2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	const	PRIMARY	PRIMARY	4	const	1	Using index
explain select 1 from t1 where id =2 or id=3;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	index	PRIMARY	PRIMARY	4	NULL	7	Using where; Using index
explain select name from t1 where id =2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	const	PRIMARY	PRIMARY	4	const	1	
ALTER TABLE t1 DROP PRIMARY KEY, ADD INDEX (id);
explain select 1 from t1 where id =2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ref	id	id	4	const	1	Using index
drop table t1;
CREATE TABLE t1 (numeropost int NOT NULL default '0', numreponse int NOT NULL auto_increment, PRIMARY KEY (numeropost,numreponse), UNIQUE KEY numreponse (numreponse));
INSERT INTO t1 (numeropost,numreponse) VALUES ('1','1'),('1','2'),('2','3'),('2','4');
SELECT numeropost FROM t1 WHERE numreponse='1';
numeropost
1
EXPLAIN SELECT numeropost FROM t1 WHERE numreponse='1';
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	const	numreponse	numreponse	4	const	1	Using index
FLUSH TABLES;
SELECT numeropost FROM t1 WHERE numreponse='1';
numeropost
1
drop table t1;
create table t1 (c varchar(30), t text, unique (c(2)), unique (t(3))) engine=myisam;
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `c` varchar(30) DEFAULT NULL,
  `t` text,
  UNIQUE KEY `c` (`c`()),
  UNIQUE KEY `t` (`t`())
) ENGINE=MyISAM
insert t1 values ('cccc', 'tttt'),
(0xD0B1212223D0B1D0B1D0B1D0B1D0B1, 0xD0B1D0B1212223D0B1D0B1D0B1D0B1),
(0xD0B1222123D0B1D0B1D0B1D0B1D0B1, 0xD0B1D0B1222123D0B1D0B1D0B1D0B1);
insert t1 (c) values ('cc22');
ERROR 23000: Duplicate entry 'cc' for key 'c'
insert t1 (t) values ('ttt22');
ERROR 23000: Duplicate entry 'ttt' for key 't'
insert t1 (c) values (0xD0B1212322D0B1D0B1D0B1D0B1D0B1);
ERROR 23000: Duplicate entry 'б!' for key 'c'
insert t1 (t) values (0xD0B1D0B1212322D0B1D0B1D0B1D0B1);
ERROR 23000: Duplicate entry 'бб!' for key 't'
select c from t1 where c='cccc';
c
cccc
select t from t1 where t='tttt';
t
tttt
select c from t1 where c=0xD0B1212223D0B1D0B1D0B1D0B1D0B1;
c
б!"#ббббб
select t from t1 where t=0xD0B1D0B1212223D0B1D0B1D0B1D0B1;
t
бб!"#бббб
drop table t1;
DROP TABLE IF EXISTS t1;
Warnings:
Note	1051	Unknown table 't1'
CREATE TABLE t1 (
c1 int,
c2 varbinary(240),
UNIQUE KEY (c1),
KEY (c2)
) ENGINE=MyISAM;
INSERT INTO t1 VALUES (1,'\Z\Z\Z\Z');
INSERT INTO t1 VALUES (2,'\Z\Z\Z\Z\Z\Z');
INSERT INTO t1 VALUES (3,'\Z\Z\Z\Z');
select c1 from t1 where c2='\Z\Z\Z\Z';
c1
1
3
DELETE FROM t1 WHERE (c1 = 1);
check table t1;
Table	Op	Msg_type	Msg_text
test.t1	check	status	OK
select c1 from t1 where c2='\Z\Z\Z\Z';
c1
3
DELETE FROM t1 WHERE (c1 = 3);
check table t1;
Table	Op	Msg_type	Msg_text
test.t1	check	status	OK
select c1 from t1 where c2='\Z\Z\Z\Z';
c1
truncate table t1;
insert into t1 values(1,"aaaa"),(2,"aaab"),(3,"aaac"),(4,"aaccc");
delete from t1 where c1=3;
delete from t1 where c1=1;
delete from t1 where c1=4;
check table t1;
Table	Op	Msg_type	Msg_text
test.t1	check	status	OK
drop table t1;
create table t1 (c char(10), index (c(0)));
ERROR HY000: Key part 'c' length cannot be 0
create table t1 (c char(10), index (c,c));
ERROR 42S21: Duplicate column name 'c'
create table t1 (c1 char(10), c2 char(10), index (c1,c2,c1));
ERROR 42S21: Duplicate column name 'c1'
create table t1 (c1 char(10), c2 char(10), index (c1,c1,c2));
ERROR 42S21: Duplicate column name 'c1'
create table t1 (c1 char(10), c2 char(10), index (c2,c1,c1));
ERROR 42S21: Duplicate column name 'c1'
create table t1 (c1 char(10), c2 char(10));
alter table t1 add key (c1,c1);
ERROR 42S21: Duplicate column name 'c1'
alter table t1 add key (c2,c1,c1);
ERROR 42S21: Duplicate column name 'c1'
alter table t1 add key (c1,c2,c1);
ERROR 42S21: Duplicate column name 'c1'
alter table t1 add key (c1,c1,c2);
ERROR 42S21: Duplicate column name 'c1'
drop table t1;
create table t1 (
i1 INT NOT NULL,
i2 INT NOT NULL,
UNIQUE i1idx (i1),
UNIQUE i2idx (i2));
desc t1;
Field	Type	Null	Key	Default	Extra
i1	int	NO	PRI	NULL	
i2	int	NO	UNI	NULL	
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `i1` int NOT NULL,
  `i2` int NOT NULL,
  UNIQUE KEY `i1idx` (`i1`),
  UNIQUE KEY `i2idx` (`i2`)
) ENGINE=InnoDB
drop table t1;
create table t1 (
c1 int,
c2 varchar(20) not null,
primary key (c1),
key (c2(10))
) engine=myisam;
insert into t1 values (1,'');
insert into t1 values (2,' \t\tTest String');
insert into t1 values (3,' \n\tTest String');
update t1 set c2 = 'New Test String' where c1 = 1;
select * from t1;
c1	c2
1	New Test String
2	 		Test String
3	 
	Test String
drop table t1;
create table t1 (a varchar(10), b varchar(10), key(a(10),b(10)));
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `a` varchar(10) DEFAULT NULL,
  `b` varchar(10) DEFAULT NULL,
  KEY `a` (`a`,`b`)
) ENGINE=InnoDB
alter table t1 modify b varchar(20);
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `a` varchar(10) DEFAULT NULL,
  `b` varchar(20) DEFAULT NULL,
  KEY `a` (`a`,`b`)
) ENGINE=InnoDB
alter table t1 modify a varchar(20);
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `a` varchar(20) DEFAULT NULL,
  `b` varchar(20) DEFAULT NULL,
  KEY `a` (`a`,`b`)
) ENGINE=InnoDB
drop table t1;
create table t1 (a int not null primary key, b varchar(20) not null unique);
desc t1;
Field	Type	Null	Key	Default	Extra
a	int	NO	PRI	NULL	
b	varchar(20)	NO	UNI	NULL	
drop table t1;
create table t1 (a int not null primary key, b int not null unique);
desc t1;
Field	Type	Null	Key	Default	Extra
a	int	NO	PRI	NULL	
b	int	NO	UNI	NULL	
drop table t1;
create table t1 (a int not null primary key, b varchar(20) not null, unique (b(10)));
desc t1;
Field	Type	Null	Key	Default	Extra
a	int	NO	PRI	NULL	
b	varchar(20)	NO	UNI	NULL	
drop table t1;
create table t1 (a int not null primary key, b varchar(20) not null, c varchar(20) not null, unique(b(10),c(10)));
desc t1;
Field	Type	Null	Key	Default	Extra
a	int	NO	PRI	NULL	
b	varchar(20)	NO	MUL	NULL	
c	varchar(20)	NO		NULL	
drop table t1;
create table t1 (
c1 int,
c2 char(12),
c3 varchar(123),
c4 timestamp,
index (c1),
index i1 (c1),
index i2 (c2),
index i3 (c3),
unique i4 (c4),
index i5 (c1, c2, c3, c4),
primary key (c2, c3),
index (c2, c4));
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `c1` int DEFAULT NULL,
  `c2` varchar(12) NOT NULL,
  `c3` varchar(123) NOT NULL,
  `c4` timestamp NULL DEFAULT NULL,
  PRIMARY KEY (`c2`,`c3`),
  UNIQUE KEY `i4` (`c4`),
  KEY `c1` (`c1`),
  KEY `i1` (`c1`),
  KEY `i2` (`c2`),
  KEY `i3` (`c3`),
  KEY `i5` (`c1`,`c2`,`c3`,`c4`),
  KEY `c2` (`c2`,`c4`)
) ENGINE=InnoDB
alter table t1 drop index c1;
alter table t1 add index (c1);
alter table t1 add index (c1);
alter table t1 drop index i3;
alter table t1 add index i3 (c3);
alter table t1 drop index i2, drop index i4;
alter table t1 add index i2 (c2), add index i4 (c4);
alter table t1 drop index i2, drop index i4, add index i6 (c2, c4);
alter table t1 add index i2 (c2), add index i4 (c4), drop index i6;
alter table t1 drop index i2, drop index i4, add unique i4 (c4);
alter table t1 add index i2 (c2), drop index i4, add index i4 (c4);
alter table t1 drop index c2, add index (c2(4),c3(7));
alter table t1 drop index c2, add index (c2(4),c3(7));
alter table t1 add primary key (c1, c2), drop primary key;
alter table t1 drop primary key;
alter table t1 add primary key (c1, c2), drop primary key;
ERROR 42000: Can't DROP 'PRIMARY'; check that column/key exists
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `c1` int NOT NULL,
  `c2` varchar(12) NOT NULL,
  `c3` varchar(123) NOT NULL,
  `c4` timestamp NULL DEFAULT NULL,
  KEY `i1` (`c1`),
  KEY `i5` (`c1`,`c2`,`c3`,`c4`),
  KEY `c1` (`c1`),
  KEY `c1_2` (`c1`),
  KEY `i3` (`c3`),
  KEY `i2` (`c2`),
  KEY `i4` (`c4`),
  KEY `c2` (`c2`(),`c3`())
) ENGINE=InnoDB
insert into t1 values(1, 'a', 'a', NULL);
insert into t1 values(1, 'b', 'b', NULL);
alter table t1 drop index i3, drop index i2, drop index i1;
alter table t1 add index i3 (c3), add index i2 (c2), add unique index i1 (c1);
ERROR 23000: Duplicate entry '1' for key 'i1'
drop table t1;
CREATE TABLE t1( a int, KEY(a) ) ENGINE=MyISAM;
INSERT INTO t1 VALUES( 1 );
ALTER TABLE t1 DISABLE KEYS;
EXPLAIN SELECT MAX(a) FROM t1 FORCE INDEX(a);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	system	NULL	NULL	NULL	NULL	1	
drop table t1;
CREATE TABLE t1 (
a INTEGER auto_increment PRIMARY KEY,
b INTEGER NOT NULL,
c INTEGER NOT NULL,
d CHAR(64)
);
CREATE TABLE t2 (
a INTEGER auto_increment PRIMARY KEY,
b INTEGER NOT NULL,
c int NOT NULL,
d DATETIME NOT NULL,
e int NOT NULL,
f INTEGER NOT NULL,
g INTEGER NOT NULL,  
h int NOT NULL,
i INTEGER NOT NULL,
j INTEGER NOT NULL,
UNIQUE INDEX (b),
INDEX (b, d, e, f, g, h, i, j, c),
INDEX (c)
);
INSERT INTO t2 VALUES 
(NULL, 1, 254, '1000-01-01 00:00:00', 257, 0, 0, 0, 0, 0),
(NULL, 2, 1, '2004-11-30 12:00:00', 1, 0, 0, 0, 0, 0),
(NULL, 3, 1, '2004-11-30 12:00:00', 1, 0, 0, 2, -21600, 0),
(NULL, 4, 1, '2004-11-30 12:00:00', 1, 0, 0, 2, -10800, 0),
(NULL, 5, 1, '2004-11-30 12:00:00', 1, 0, 0, 5, -10800, 0),
(NULL, 6, 1, '2004-11-30 12:00:00', 102, 0, 0, 0, 0, 0),
(NULL, 7, 1, '2004-11-30 12:00:00', 105, 2, 0, 0, 0, 0),
(NULL, 8, 1, '2004-11-30 12:00:00', 105, 10, 0, 0, 0, 0);
INSERT INTO t1 (b, c, d) VALUES
(3388000, -553000, NULL),
(3388000, -553000, NULL);
DROP TABLE t1, t2;
create table t1(a int not null, key aa(a), 
b char(10) not null, unique key bb(b(1)), 
c char(4) not null, unique key cc(c));
desc t1;
Field	Type	Null	Key	Default	Extra
a	int	NO	MUL	NULL	
b	varchar(10)	NO	UNI	NULL	
c	varchar(4)	NO	PRI	NULL	
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `a` int NOT NULL,
  `b` varchar(10) NOT NULL,
  `c` varchar(4) NOT NULL,
  UNIQUE KEY `cc` (`c`),
  UNIQUE KEY `bb` (`b`()),
  KEY `aa` (`a`)
) ENGINE=InnoDB
drop table t1;
create table t1(a int not null, key aa(a), 
b char(10) not null, unique key bb(b(1)),
c char(4) not null);
desc t1;
Field	Type	Null	Key	Default	Extra
a	int	NO	MUL	NULL	
b	varchar(10)	NO	UNI	NULL	
c	varchar(4)	NO		NULL	
alter table t1 add unique key cc(c);
desc t1;
Field	Type	Null	Key	Default	Extra
a	int	NO	MUL	NULL	
b	varchar(10)	NO	UNI	NULL	
c	varchar(4)	NO	PRI	NULL	
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `a` int NOT NULL,
  `b` varchar(10) NOT NULL,
  `c` varchar(4) NOT NULL,
  UNIQUE KEY `cc` (`c`),
  UNIQUE KEY `bb` (`b`()),
  KEY `aa` (`a`)
) ENGINE=InnoDB
drop table t1;
End of 5.0 tests
DROP TABLE IF EXISTS t1;
CREATE TABLE t1 (a INT PRIMARY KEY AUTO_INCREMENT);
INSERT INTO t1 VALUES (), (), ();
SELECT 1 AS c1
FROM t1
ORDER BY (
SELECT 1 AS c2
FROM t1
GROUP BY GREATEST(LAST_INSERT_ID(), t1.a) ASC
LIMIT 1);
c1
1
1
1
DROP TABLE t1;
CREATE TABLE t1 (a INT, b INT, INDEX (a,b));
INSERT INTO t1 (a, b)
VALUES
(1,1), (1,2), (1,3), (1,4), (1,5),
(2,2), (2,3), (2,1), (3,1), (4,1), (4,2), (4,3), (4,4), (4,5), (4,6);
EXPLAIN SELECT 1 FROM t1 AS t1_outer WHERE 
(SELECT max(b) FROM t1 GROUP BY a HAVING a < 2) > 12;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
2	SUBQUERY	t1	range	NULL	a	5	NULL	3	Using index for group-by
SELECT 1 as RES FROM t1 AS t1_outer WHERE 
(SELECT max(b) FROM t1 GROUP BY a HAVING a < 2) > 12;
RES
DROP TABLE t1;