SET SESSION STORAGE_ENGINE = MEMORY; drop table if exists t1,t2,t3,t4; drop database if exists mysqltest; create table t1 (id int unsigned not null auto_increment, code tinyint unsigned not null, name char(20) not null, primary key (id), key (code), unique (name)) engine=MyISAM; insert into t1 (code, name) values (1, 'Tim'), (1, 'Monty'), (2, 'David'), (2, 'Erik'), (3, 'Sasha'), (3, 'Jeremy'), (4, 'Matt'); select id, code, name from t1 order by id; id code name 1 1 Tim 2 1 Monty 3 2 David 4 2 Erik 5 3 Sasha 6 3 Jeremy 7 4 Matt update ignore t1 set id = 8, name = 'Sinisa' where id < 3; select id, code, name from t1 order by id; id code name 2 1 Monty 3 2 David 4 2 Erik 5 3 Sasha 6 3 Jeremy 7 4 Matt 8 1 Sinisa update ignore t1 set id = id + 10, name = 'Ralph' where id < 4; select id, code, name from t1 order by id; id code name 3 2 David 4 2 Erik 5 3 Sasha 6 3 Jeremy 7 4 Matt 8 1 Sinisa 12 1 Ralph drop table t1; CREATE TABLE t1 ( id int(11) NOT NULL auto_increment, parent_id int(11) DEFAULT '0' NOT NULL, level tinyint(4) DEFAULT '0' NOT NULL, PRIMARY KEY (id), KEY parent_id (parent_id), KEY level (level) ) engine=MyISAM; INSERT INTO t1 VALUES (1,0,0),(3,1,1),(4,1,1),(8,2,2),(9,2,2),(17,3,2),(22,4,2),(24,4,2),(28,5,2),(29,5,2),(30,5,2),(31,6,2),(32,6,2),(33,6,2),(203,7,2),(202,7,2),(20,3,2),(157,0,0),(193,5,2),(40,7,2),(2,1,1),(15,2,2),(6,1,1),(34,6,2),(35,6,2),(16,3,2),(7,1,1),(36,7,2),(18,3,2),(26,5,2),(27,5,2),(183,4,2),(38,7,2),(25,5,2),(37,7,2),(21,4,2),(19,3,2),(5,1,1),(179,5,2); update t1 set parent_id=parent_id+100; select * from t1 where parent_id=102; id parent_id level 8 102 2 9 102 2 15 102 2 update t1 set id=id+1000; update t1 set id=1024 where id=1009; Got one of the listed errors select * from t1; id parent_id level 1001 100 0 1003 101 1 1004 101 1 1008 102 2 1009 102 2 1017 103 2 1022 104 2 1024 104 2 1028 105 2 1029 105 2 1030 105 2 1031 106 2 1032 106 2 1033 106 2 1203 107 2 1202 107 2 1020 103 2 1157 100 0 1193 105 2 1040 107 2 1002 101 1 1015 102 2 1006 101 1 1034 106 2 1035 106 2 1016 103 2 1007 101 1 1036 107 2 1018 103 2 1026 105 2 1027 105 2 1183 104 2 1038 107 2 1025 105 2 1037 107 2 1021 104 2 1019 103 2 1005 101 1 1179 105 2 update ignore t1 set id=id+1; select * from t1; id parent_id level 1001 100 0 1003 101 1 1004 101 1 1008 102 2 1010 102 2 1017 103 2 1023 104 2 1024 104 2 1028 105 2 1029 105 2 1030 105 2 1031 106 2 1032 106 2 1033 106 2 1204 107 2 1203 107 2 1020 103 2 1158 100 0 1194 105 2 1041 107 2 1002 101 1 1015 102 2 1006 101 1 1034 106 2 1035 106 2 1016 103 2 1007 101 1 1036 107 2 1018 103 2 1026 105 2 1027 105 2 1184 104 2 1039 107 2 1025 105 2 1038 107 2 1022 104 2 1019 103 2 1005 101 1 1180 105 2 update ignore t1 set id=1023 where id=1010; select * from t1 where parent_id=102; id parent_id level 1008 102 2 1010 102 2 1015 102 2 explain select level from t1 where level=1; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref level level 1 const # Using index explain select level,id from t1 where level=1; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref level level 1 const # explain select level,id,parent_id from t1 where level=1; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref level level 1 const # select level,id from t1 where level=1; level id 1 1003 1 1004 1 1002 1 1006 1 1007 1 1005 select level,id,parent_id from t1 where level=1; level id parent_id 1 1003 101 1 1004 101 1 1002 101 1 1006 101 1 1007 101 1 1005 101 optimize table t1; Table Op Msg_type Msg_text test.t1 optimize status OK 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 id A # NULL NULL BTREE t1 1 parent_id 1 parent_id A # NULL NULL BTREE t1 1 level 1 level A # NULL NULL BTREE drop table t1; CREATE TABLE t1 ( gesuchnr int(11) DEFAULT '0' NOT NULL, benutzer_id int(11) DEFAULT '0' NOT NULL, PRIMARY KEY (gesuchnr,benutzer_id) ) engine=MyISAM; replace into t1 (gesuchnr,benutzer_id) values (2,1); replace into t1 (gesuchnr,benutzer_id) values (1,1); replace into t1 (gesuchnr,benutzer_id) values (1,1); select * from t1; gesuchnr benutzer_id 1 1 2 1 drop table t1; create table t1 (a int) engine=MyISAM; insert into t1 values (1), (2); optimize table t1; Table Op Msg_type Msg_text test.t1 optimize status OK delete from t1 where a = 1; select * from t1; a 2 check table t1; Table Op Msg_type Msg_text test.t1 check status OK drop table t1; create table t1 (a int,b varchar(20)) engine=MyISAM; insert into t1 values (1,""), (2,"testing"); delete from t1 where a = 1; select * from t1; a b 2 testing create index skr on t1 (a); insert into t1 values (3,""), (4,"testing"); analyze table t1; Table Op Msg_type Msg_text test.t1 analyze status OK 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 1 skr 1 a A # NULL NULL YES BTREE drop table t1; create table t1 (a int,b varchar(20),key(a)) engine=MyISAM; insert into t1 values (1,""), (2,"testing"); select * from t1 where a = 1; a b 1 drop table t1; CREATE TABLE t1 ( user_id int(10) DEFAULT '0' NOT NULL, name varchar(100), phone varchar(100), ref_email varchar(100) DEFAULT '' NOT NULL, detail varchar(200), PRIMARY KEY (user_id,ref_email) )engine=MyISAM; INSERT INTO t1 VALUES (10292,'sanjeev','29153373','sansh777@hotmail.com','xxx'),(10292,'shirish','2333604','shirish@yahoo.com','ddsds'),(10292,'sonali','323232','sonali@bolly.com','filmstar'); select * from t1 where user_id=10292; user_id name phone ref_email detail 10292 sanjeev 29153373 sansh777@hotmail.com xxx 10292 shirish 2333604 shirish@yahoo.com ddsds 10292 sonali 323232 sonali@bolly.com filmstar INSERT INTO t1 VALUES (10291,'sanjeev','29153373','sansh777@hotmail.com','xxx'),(10293,'shirish','2333604','shirish@yahoo.com','ddsds'); select * from t1 where user_id=10292; user_id name phone ref_email detail 10292 sanjeev 29153373 sansh777@hotmail.com xxx 10292 shirish 2333604 shirish@yahoo.com ddsds 10292 sonali 323232 sonali@bolly.com filmstar select * from t1 where user_id>=10292; user_id name phone ref_email detail 10292 sanjeev 29153373 sansh777@hotmail.com xxx 10292 shirish 2333604 shirish@yahoo.com ddsds 10292 sonali 323232 sonali@bolly.com filmstar 10293 shirish 2333604 shirish@yahoo.com ddsds select * from t1 where user_id>10292; user_id name phone ref_email detail 10293 shirish 2333604 shirish@yahoo.com ddsds select * from t1 where user_id<10292; user_id name phone ref_email detail 10291 sanjeev 29153373 sansh777@hotmail.com xxx drop table t1; CREATE TABLE t1 (a int not null, b int not null,c int not null, key(a),primary key(a,b), unique(c),key(a),unique(b)) ENGINE = MyISAM; Warnings: Note 1831 Duplicate index `a_2`. This is deprecated and will be disallowed in a future release. show index 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 a A # NULL NULL BTREE t1 0 PRIMARY 2 b A # NULL NULL BTREE t1 0 c 1 c A # NULL NULL BTREE t1 0 b 1 b A # NULL NULL BTREE t1 1 a 1 a A # NULL NULL BTREE t1 1 a_2 1 a A # NULL NULL BTREE drop table t1; create table t1 (col1 int not null, col2 char(4) not null, primary key(col1)) ENGINE = MEMORY; alter table t1 engine=MyISAM; insert into t1 values ('1','1'),('5','2'),('2','3'),('3','4'),('4','4'); select * from t1; col1 col2 1 1 5 2 2 3 3 4 4 4 update t1 set col2='7' where col1='4'; select * from t1; col1 col2 1 1 5 2 2 3 3 4 4 7 alter table t1 add co3 int not null; select * from t1; col1 col2 co3 1 1 0 5 2 0 2 3 0 3 4 0 4 7 0 update t1 set col2='9' where col1='2'; select * from t1; col1 col2 co3 1 1 0 5 2 0 2 9 0 3 4 0 4 7 0 drop table t1; create table t1 (a int not null , b int, primary key (a)) engine = MyISAM; create table t2 (a int not null , b int, primary key (a)) engine = MEMORY; insert into t1 VALUES (1,3) , (2,3), (3,3); select * from t1; a b 1 3 2 3 3 3 insert into t2 select * from t1; select * from t2; a b 1 3 2 3 3 3 delete from t1 where b = 3; select * from t1; a b insert into t1 select * from t2; select * from t1; a b 3 3 2 3 1 3 select * from t2; a b 1 3 2 3 3 3 drop table t1,t2; CREATE TABLE t1 ( id int(11) NOT NULL auto_increment, ggid varchar(32) binary DEFAULT '' NOT NULL, email varchar(64) DEFAULT '' NOT NULL, passwd varchar(32) binary DEFAULT '' NOT NULL, PRIMARY KEY (id), UNIQUE ggid (ggid) ) ENGINE=MyISAM; insert into t1 (ggid,passwd) values ('test1','xxx'); insert into t1 (ggid,passwd) values ('test2','yyy'); insert into t1 (ggid,passwd) values ('test2','this will fail'); ERROR 23000: Duplicate entry 'test2' for key 'ggid' insert into t1 (ggid,id) values ('this will fail',1); ERROR 23000: Duplicate entry '1' for key 'PRIMARY' select * from t1 where ggid='test1'; id ggid email passwd 1 test1 xxx select * from t1 where passwd='xxx'; id ggid email passwd 1 test1 xxx select * from t1 where id=2; id ggid email passwd 2 test2 yyy replace into t1 (ggid,id) values ('this will work',1); replace into t1 (ggid,passwd) values ('test2','this will work'); update t1 set id=100,ggid='test2' where id=1; ERROR 23000: Duplicate entry 'test2' for key 'ggid' select * from t1; id ggid email passwd 1 this will work 3 test2 this will work select * from t1 where id=1; id ggid email passwd 1 this will work select * from t1 where id=999; id ggid email passwd drop table t1; CREATE TABLE t1 ( user_name varchar(12), password text, subscribed char(1), user_id int(11) DEFAULT '0' NOT NULL, quota bigint(20), weight double, access_date date, access_time time, approved datetime, dummy_primary_key int(11) NOT NULL auto_increment, PRIMARY KEY (dummy_primary_key) ) ENGINE=MyISAM; INSERT INTO t1 VALUES ('user_0','somepassword','N',0,0,0,'2000-09-07','23:06:59','2000-09-07 23:06:59',1); INSERT INTO t1 VALUES ('user_1','somepassword','Y',1,1,1,'2000-09-07','23:06:59','2000-09-07 23:06:59',2); INSERT INTO t1 VALUES ('user_2','somepassword','N',2,2,1.4142135623731,'2000-09-07','23:06:59','2000-09-07 23:06:59',3); INSERT INTO t1 VALUES ('user_3','somepassword','Y',3,3,1.7320508075689,'2000-09-07','23:06:59','2000-09-07 23:06:59',4); INSERT INTO t1 VALUES ('user_4','somepassword','N',4,4,2,'2000-09-07','23:06:59','2000-09-07 23:06:59',5); select user_name, password , subscribed, user_id, quota, weight, access_date, access_time, approved, dummy_primary_key from t1 order by user_name; user_name password subscribed user_id quota weight access_date access_time approved dummy_primary_key user_0 somepassword N 0 0 0 2000-09-07 23:06:59 2000-09-07 23:06:59 1 user_1 somepassword Y 1 1 1 2000-09-07 23:06:59 2000-09-07 23:06:59 2 user_2 somepassword N 2 2 1.4142135623731 2000-09-07 23:06:59 2000-09-07 23:06:59 3 user_3 somepassword Y 3 3 1.7320508075689 2000-09-07 23:06:59 2000-09-07 23:06:59 4 user_4 somepassword N 4 4 2 2000-09-07 23:06:59 2000-09-07 23:06:59 5 drop table t1; CREATE TABLE t1 ( id int(11) NOT NULL auto_increment, parent_id int(11) DEFAULT '0' NOT NULL, level tinyint(4) DEFAULT '0' NOT NULL, KEY (id), KEY parent_id (parent_id), KEY level (level) ) engine=MyISAM; INSERT INTO t1 VALUES (1,0,0),(3,1,1),(4,1,1),(8,2,2),(9,2,2),(17,3,2),(22,4,2),(24,4,2),(28,5,2),(29,5,2),(30,5,2),(31,6,2),(32,6,2),(33,6,2),(203,7,2),(202,7,2),(20,3,2),(157,0,0),(193,5,2),(40,7,2),(2,1,1),(15,2,2),(6,1,1),(34,6,2),(35,6,2),(16,3,2),(7,1,1),(36,7,2),(18,3,2),(26,5,2),(27,5,2),(183,4,2),(38,7,2),(25,5,2),(37,7,2),(21,4,2),(19,3,2),(5,1,1); INSERT INTO t1 values (179,5,2); update t1 set parent_id=parent_id+100; select * from t1 where parent_id=102; id parent_id level 8 102 2 9 102 2 15 102 2 update t1 set id=id+1000; update t1 set id=1024 where id=1009; select * from t1; id parent_id level 1001 100 0 1003 101 1 1004 101 1 1008 102 2 1024 102 2 1017 103 2 1022 104 2 1024 104 2 1028 105 2 1029 105 2 1030 105 2 1031 106 2 1032 106 2 1033 106 2 1203 107 2 1202 107 2 1020 103 2 1157 100 0 1193 105 2 1040 107 2 1002 101 1 1015 102 2 1006 101 1 1034 106 2 1035 106 2 1016 103 2 1007 101 1 1036 107 2 1018 103 2 1026 105 2 1027 105 2 1183 104 2 1038 107 2 1025 105 2 1037 107 2 1021 104 2 1019 103 2 1005 101 1 1179 105 2 update ignore t1 set id=id+1; select * from t1; id parent_id level 1002 100 0 1004 101 1 1005 101 1 1009 102 2 1025 102 2 1018 103 2 1023 104 2 1025 104 2 1029 105 2 1030 105 2 1031 105 2 1032 106 2 1033 106 2 1034 106 2 1204 107 2 1203 107 2 1021 103 2 1158 100 0 1194 105 2 1041 107 2 1003 101 1 1016 102 2 1007 101 1 1035 106 2 1036 106 2 1017 103 2 1008 101 1 1037 107 2 1019 103 2 1027 105 2 1028 105 2 1184 104 2 1039 107 2 1026 105 2 1038 107 2 1022 104 2 1020 103 2 1006 101 1 1180 105 2 update ignore t1 set id=1023 where id=1010; select * from t1 where parent_id=102; id parent_id level 1009 102 2 1025 102 2 1016 102 2 explain select level from t1 where level=1; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref level level 1 const # Using index select level,id from t1 where level=1; level id 1 1004 1 1005 1 1003 1 1007 1 1008 1 1006 select level,id,parent_id from t1 where level=1; level id parent_id 1 1004 101 1 1005 101 1 1003 101 1 1007 101 1 1008 101 1 1006 101 select level,id from t1 where level=1 order by id; level id 1 1003 1 1004 1 1005 1 1006 1 1007 1 1008 delete from t1 where level=1; select * from t1; id parent_id level 1002 100 0 1009 102 2 1025 102 2 1018 103 2 1023 104 2 1025 104 2 1029 105 2 1030 105 2 1031 105 2 1032 106 2 1033 106 2 1034 106 2 1204 107 2 1203 107 2 1021 103 2 1158 100 0 1194 105 2 1041 107 2 1016 102 2 1035 106 2 1036 106 2 1017 103 2 1037 107 2 1019 103 2 1027 105 2 1028 105 2 1184 104 2 1039 107 2 1026 105 2 1038 107 2 1022 104 2 1020 103 2 1180 105 2 drop table t1; CREATE TABLE t1 ( sca_code char(6) NOT NULL, cat_code char(6) NOT NULL, sca_desc varchar(50), lan_code char(2) NOT NULL, sca_pic varchar(100), sca_sdesc varchar(50), sca_sch_desc varchar(16), PRIMARY KEY (sca_code, cat_code, lan_code), INDEX sca_pic (sca_pic) ) engine = MyISAM ; INSERT INTO t1 ( sca_code, cat_code, sca_desc, lan_code, sca_pic, sca_sdesc, sca_sch_desc) VALUES ( 'PD', 'J', 'PENDANT', 'EN', NULL, NULL, 'PENDANT'),( 'RI', 'J', 'RING', 'EN', NULL, NULL, 'RING'),( 'QQ', 'N', 'RING', 'EN', 'not null', NULL, 'RING'); select count(*) from t1 where sca_code = 'PD'; count(*) 1 select count(*) from t1 where sca_code <= 'PD'; count(*) 1 select count(*) from t1 where sca_pic is null; count(*) 2 alter table t1 drop index sca_pic, add index sca_pic (cat_code, sca_pic); select count(*) from t1 where sca_code='PD' and sca_pic is null; count(*) 1 select count(*) from t1 where cat_code='E'; count(*) 0 alter table t1 drop index sca_pic, add index (sca_pic, cat_code); select count(*) from t1 where sca_code='PD' and sca_pic is null; count(*) 1 select count(*) from t1 where sca_pic >= 'n'; count(*) 1 select sca_pic from t1 where sca_pic is null; sca_pic NULL NULL update t1 set sca_pic="test" where sca_pic is null; delete from t1 where sca_code='pd'; drop table t1; set @a:=now(); CREATE TABLE t1 (a int not null, b timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP, primary key (a)) engine=MyISAM; insert into t1 (a) values(1),(2),(3); select t1.a from t1 natural join t1 as t2 where t1.b >= @a order by t1.a; a 1 2 3 select a from t1 natural join t1 as t2 where b >= @a order by a; a 1 2 3 update t1 set a=5 where a=1; select a from t1; a 2 3 5 drop table t1; create table t1 (a varchar(100) not null, primary key(a), b int not null) engine=MyISAM; insert into t1 values("hello",1),("world",2); select * from t1 order by b desc; a b world 2 hello 1 optimize table t1; Table Op Msg_type Msg_text test.t1 optimize status OK 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 a A # NULL NULL BTREE drop table t1; create table t1 (i int, j int ) ENGINE=MyISAM; insert into t1 values (1,2); select * from t1 where i=1 and j=2; i j 1 2 create index ax1 on t1 (i,j); select * from t1 where i=1 and j=2; i j 1 2 drop table t1; CREATE TABLE t1 ( a int3 unsigned NOT NULL, b int1 unsigned NOT NULL, UNIQUE (a, b) ) ENGINE = MyISAM; INSERT INTO t1 VALUES (1, 1); SELECT MIN(B),MAX(b) FROM t1 WHERE t1.a = 1; MIN(B) MAX(b) 1 1 drop table t1; CREATE TABLE t1 (a int unsigned NOT NULL) engine=MyISAM; INSERT INTO t1 VALUES (1); SELECT * FROM t1; a 1 DROP TABLE t1; create table t1 (a int primary key,b int, c int, d int, e int, f int, g int, h int, i int, j int, k int, l int, m int, n int, o int, p int, q int, r int, s int, t int, u int, v int, w int, x int, y int, z int, a1 int, a2 int, a3 int, a4 int, a5 int, a6 int, a7 int, a8 int, a9 int, b1 int, b2 int, b3 int, b4 int, b5 int, b6 int) engine = MyISAM; insert into t1 values (1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1); explain select * from t1 where a > 0 and a < 50; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 system PRIMARY NULL NULL NULL # drop table t1; create table t1 (id int NOT NULL,id2 int NOT NULL,id3 int NOT NULL,dummy1 char(30),primary key (id,id2),index index_id3 (id3)) engine=MyISAM; insert into t1 values (0,0,0,'ABCDEFGHIJ'),(2,2,2,'BCDEFGHIJK'),(1,1,1,'CDEFGHIJKL'); LOCK TABLES t1 WRITE; insert into t1 values (99,1,2,'D'),(1,1,2,'D'); ERROR 23000: Duplicate entry '1-1' for key 'PRIMARY' select id from t1; id 0 1 2 99 select id from t1; id 0 1 2 99 UNLOCK TABLES; DROP TABLE t1; create table t1 (id int NOT NULL,id2 int NOT NULL,id3 int NOT NULL,dummy1 char(30),primary key (id,id2),index index_id3 (id3)) engine=MyISAM; insert into t1 values (0,0,0,'ABCDEFGHIJ'),(2,2,2,'BCDEFGHIJK'),(1,1,1,'CDEFGHIJKL'); LOCK TABLES t1 WRITE; begin; insert into t1 values (99,1,2,'D'),(1,1,2,'D'); ERROR 23000: Duplicate entry '1-1' for key 'PRIMARY' select id from t1; id 0 1 2 99 insert ignore into t1 values (100,1,2,'D'),(1,1,99,'D'); Warnings: Warning 1062 Duplicate entry '1-1' for key 'PRIMARY' commit; select id,id3 from t1; id id3 0 0 2 2 1 1 99 2 100 2 UNLOCK TABLES; DROP TABLE t1; create table t1 (a char(20), unique (a(5))) engine=MyISAM; drop table t1; create table t1 (a char(20), index (a(5))) engine=MyISAM; show create table t1; Table Create Table t1 CREATE TABLE `t1` ( `a` char(20) DEFAULT NULL, KEY `a` (`a`(5)) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 drop table t1; create temporary table t1 (a int not null auto_increment, primary key(a)) engine=MyISAM; insert into t1 values (NULL),(NULL),(NULL); delete from t1 where a=3; insert into t1 values (NULL); select * from t1; a 1 2 4 alter table t1 add b int; select * from t1; a b 1 NULL 2 NULL 4 NULL drop table t1; create table t1 ( id int auto_increment primary key, name varchar(32) not null, value text not null, uid int not null, unique key(name,uid) ) engine=MyISAM; insert into t1 values (1,'one','one value',101), (2,'two','two value',102),(3,'three','three value',103); set insert_id=5; replace into t1 (value,name,uid) values ('other value','two',102); delete from t1 where uid=102; set insert_id=5; replace into t1 (value,name,uid) values ('other value','two',102); set insert_id=6; replace into t1 (value,name,uid) values ('other value','two',102); select * from t1; id name value uid 1 one one value 101 3 three three value 103 6 two other value 102 drop table t1; create database mysqltest; create table mysqltest.t1 (a int not null) engine= MyISAM; insert into mysqltest.t1 values(1); create table mysqltest.t2 (a int not null) engine= MEMORY; insert into mysqltest.t2 values(1); create table mysqltest.t3 (a int not null) engine= MEMORY; insert into mysqltest.t3 values(1); commit; drop database mysqltest; show tables from mysqltest; ERROR 42000: Unknown database 'mysqltest' set autocommit=0; create table t1 (a int not null) engine= MyISAM; insert into t1 values(1),(2); truncate table t1; commit; truncate table t1; truncate table t1; select * from t1; a insert into t1 values(1),(2); delete from t1; select * from t1; a commit; drop table t1; set autocommit=1; create table t1 (a int not null) engine= MyISAM; insert into t1 values(1),(2); truncate table t1; insert into t1 values(1),(2); select * from t1; a 1 2 truncate table t1; insert into t1 values(1),(2); delete from t1; select * from t1; a drop table t1; create table t1 (a int not null, b int not null, c int not null, primary key (a),key(b)) engine=MyISAM; insert into t1 values (3,3,3),(1,1,1),(2,2,2),(4,4,4); explain select * from t1 order by a; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ALL NULL NULL NULL NULL # Using filesort explain select * from t1 order by b; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ALL NULL NULL NULL NULL # Using filesort explain select * from t1 order by c; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ALL NULL NULL NULL NULL # Using filesort explain select a from t1 order by a; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index NULL PRIMARY 4 NULL # Using index explain select b from t1 order by b; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index NULL b 4 NULL # Using index explain select a,b from t1 order by b; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ALL NULL NULL NULL NULL # Using filesort explain select a,b from t1; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ALL NULL NULL NULL NULL # explain select a,b,c from t1; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ALL NULL NULL NULL NULL # drop table t1; create table t1 (t int not null default 1, key (t)) engine=MyISAM; desc t1; Field Type Null Key Default Extra t int(11) NO MUL 1 drop table t1; CREATE TABLE t1 ( number bigint(20) NOT NULL default '0', cname char(15) NOT NULL default '', carrier_id smallint(6) NOT NULL default '0', privacy tinyint(4) NOT NULL default '0', last_mod_date timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP, last_mod_id smallint(6) NOT NULL default '0', last_app_date timestamp NOT NULL DEFAULT '0000-00-00 00:00:00', last_app_id smallint(6) default '-1', version smallint(6) NOT NULL default '0', assigned_scps int(11) default '0', status tinyint(4) default '0' ) ENGINE=MyISAM; INSERT INTO t1 VALUES (4077711111,'SeanWheeler',90,2,20020111112846,500,00000000000000,-1,2,3,1); INSERT INTO t1 VALUES (9197722223,'berry',90,3,20020111112809,500,20020102114532,501,4,10,0); INSERT INTO t1 VALUES (650,'San Francisco',0,0,20011227111336,342,00000000000000,-1,1,24,1); INSERT INTO t1 VALUES (302467,'Sue\'s Subshop',90,3,20020109113241,500,20020102115111,501,7,24,0); INSERT INTO t1 VALUES (6014911113,'SudzCarwash',520,1,20020102115234,500,20020102115259,501,33,32768,0); INSERT INTO t1 VALUES (333,'tubs',99,2,20020109113440,501,20020109113440,500,3,10,0); CREATE TABLE t2 ( number bigint(20) NOT NULL default '0', cname char(15) NOT NULL default '', carrier_id smallint(6) NOT NULL default '0', privacy tinyint(4) NOT NULL default '0', last_mod_date timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP, last_mod_id smallint(6) NOT NULL default '0', last_app_date timestamp NOT NULL DEFAULT '0000-00-00 00:00:00', last_app_id smallint(6) default '-1', version smallint(6) NOT NULL default '0', assigned_scps int(11) default '0', status tinyint(4) default '0' ) ENGINE=MyISAM; INSERT INTO t2 VALUES (4077711111,'SeanWheeler',0,2,20020111112853,500,00000000000000,-1,2,3,1); INSERT INTO t2 VALUES (9197722223,'berry',90,3,20020111112818,500,20020102114532,501,4,10,0); INSERT INTO t2 VALUES (650,'San Francisco',90,0,20020109113158,342,00000000000000,-1,1,24,1); INSERT INTO t2 VALUES (333,'tubs',99,2,20020109113453,501,20020109113453,500,3,10,0); select * from t1; number cname carrier_id privacy last_mod_date last_mod_id last_app_date last_app_id version assigned_scps status 4077711111 SeanWheeler 90 2 2002-01-11 11:28:46 500 0000-00-00 00:00:00 -1 2 3 1 9197722223 berry 90 3 2002-01-11 11:28:09 500 2002-01-02 11:45:32 501 4 10 0 650 San Francisco 0 0 2001-12-27 11:13:36 342 0000-00-00 00:00:00 -1 1 24 1 302467 Sue's Subshop 90 3 2002-01-09 11:32:41 500 2002-01-02 11:51:11 501 7 24 0 6014911113 SudzCarwash 520 1 2002-01-02 11:52:34 500 2002-01-02 11:52:59 501 33 32768 0 333 tubs 99 2 2002-01-09 11:34:40 501 2002-01-09 11:34:40 500 3 10 0 select * from t2; number cname carrier_id privacy last_mod_date last_mod_id last_app_date last_app_id version assigned_scps status 4077711111 SeanWheeler 0 2 2002-01-11 11:28:53 500 0000-00-00 00:00:00 -1 2 3 1 9197722223 berry 90 3 2002-01-11 11:28:18 500 2002-01-02 11:45:32 501 4 10 0 650 San Francisco 90 0 2002-01-09 11:31:58 342 0000-00-00 00:00:00 -1 1 24 1 333 tubs 99 2 2002-01-09 11:34:53 501 2002-01-09 11:34:53 500 3 10 0 delete t1, t2 from t1 left join t2 on t1.number=t2.number where (t1.carrier_id=90 and t1.number=t2.number) or (t2.carrier_id=90 and t1.number=t2.number) or (t1.carrier_id=90 and t2.number is null); select * from t1; number cname carrier_id privacy last_mod_date last_mod_id last_app_date last_app_id version assigned_scps status 6014911113 SudzCarwash 520 1 2002-01-02 11:52:34 500 2002-01-02 11:52:59 501 33 32768 0 333 tubs 99 2 2002-01-09 11:34:40 501 2002-01-09 11:34:40 500 3 10 0 select * from t2; number cname carrier_id privacy last_mod_date last_mod_id last_app_date last_app_id version assigned_scps status 333 tubs 99 2 2002-01-09 11:34:53 501 2002-01-09 11:34:53 500 3 10 0 select * from t2; number cname carrier_id privacy last_mod_date last_mod_id last_app_date last_app_id version assigned_scps status 333 tubs 99 2 2002-01-09 11:34:53 501 2002-01-09 11:34:53 500 3 10 0 drop table t1,t2; create table t1 (id int unsigned not null auto_increment, code tinyint unsigned not null, name char(20) not null, primary key (id), key (code), unique (name)) engine=MyISAM; BEGIN; SET SESSION TRANSACTION ISOLATION LEVEL SERIALIZABLE; SELECT @@tx_isolation,@@global.tx_isolation; @@tx_isolation @@global.tx_isolation SERIALIZABLE REPEATABLE-READ insert into t1 (code, name) values (1, 'Tim'), (1, 'Monty'), (2, 'David'); select id, code, name from t1 order by id; id code name 1 1 Tim 2 1 Monty 3 2 David COMMIT; BEGIN; SET SESSION TRANSACTION ISOLATION LEVEL REPEATABLE READ; insert into t1 (code, name) values (2, 'Erik'), (3, 'Sasha'); select id, code, name from t1 order by id; id code name 1 1 Tim 2 1 Monty 3 2 David 4 2 Erik 5 3 Sasha COMMIT; BEGIN; SET SESSION TRANSACTION ISOLATION LEVEL READ UNCOMMITTED; insert into t1 (code, name) values (3, 'Jeremy'), (4, 'Matt'); select id, code, name from t1 order by id; id code name 1 1 Tim 2 1 Monty 3 2 David 4 2 Erik 5 3 Sasha 6 3 Jeremy 7 4 Matt COMMIT; DROP TABLE t1; create table t1 (n int(10), d int(10)) engine=MyISAM; create table t2 (n int(10), d int(10)) engine=MyISAM; insert into t1 values(1,1),(1,2); insert into t2 values(1,10),(2,20); UPDATE t1,t2 SET t1.d=t2.d,t2.d=30 WHERE t1.n=t2.n; select * from t1; n d 1 10 1 10 select * from t2; n d 1 30 2 20 drop table t1,t2; create table t1 (a int, b int) engine=MyISAM; insert into t1 values(20,null); select t2.b, ifnull(t2.b,"this is null") from t1 as t2 left join t1 as t3 on t2.b=t3.a; b ifnull(t2.b,"this is null") NULL this is null select t2.b, ifnull(t2.b,"this is null") from t1 as t2 left join t1 as t3 on t2.b=t3.a order by 1; b ifnull(t2.b,"this is null") NULL this is null insert into t1 values(10,null); select t2.b, ifnull(t2.b,"this is null") from t1 as t2 left join t1 as t3 on t2.b=t3.a order by 1; b ifnull(t2.b,"this is null") NULL this is null NULL this is null drop table t1; create table t1 (a varchar(10) not null) engine = MEMORY; create table t2 (b varchar(10) not null unique) engine=MyISAM; select t1.a from t1,t2 where t1.a=t2.b; a drop table t1,t2; create table t1 (a int not null, b int, primary key (a)) engine = MyISAM; create table t2 (a int not null, b int, primary key (a)) engine = MyISAM; insert into t1 values (10, 20); insert into t2 values (10, 20); update t1, t2 set t1.b = 150, t2.b = t1.b where t2.a = t1.a and t1.a = 10; drop table t1,t2; CREATE TABLE t1 (a int not null primary key, b int not null, unique (b)) engine=MyISAM; INSERT INTO t1 values (1,1),(2,2),(3,3),(4,4),(5,5),(6,6),(7,7),(8,8),(9,9); UPDATE t1 set a=a+100 where b between 2 and 3 and a < 1000; SELECT * from t1; a b 1 1 102 2 103 3 4 4 5 5 6 6 7 7 8 8 9 9 drop table t1; CREATE TABLE t1 (a int not null primary key, b int not null, key (b)) engine=MyISAM; CREATE TABLE t2 (a int not null primary key, b int not null, key (b)) engine=MyISAM; INSERT INTO t1 values (1,1),(2,2),(3,3),(4,4),(5,5),(6,6),(7,7),(8,8),(9,9),(10,10),(11,11),(12,12); INSERT INTO t2 values (1,1),(2,2),(3,3),(4,4),(5,5),(6,6),(7,7),(8,8),(9,9); update t1,t2 set t1.a=t1.a+100; select * from t1; a b 101 1 102 2 103 3 104 4 105 5 106 6 107 7 108 8 109 9 110 10 111 11 112 12 update t1,t2 set t1.a=t1.a+100 where t1.a=101; select * from t1; a b 201 1 102 2 103 3 104 4 105 5 106 6 107 7 108 8 109 9 110 10 111 11 112 12 update t1,t2 set t1.b=t1.b+10 where t1.b=2; select * from t1; a b 201 1 102 12 103 3 104 4 105 5 106 6 107 7 108 8 109 9 110 10 111 11 112 12 update t1,t2 set t1.b=t1.b+2,t2.b=t1.b+10 where t1.b between 3 and 5 and t1.a=t2.a+100; select * from t1; a b 201 1 102 12 103 5 104 6 105 7 106 6 107 7 108 8 109 9 110 10 111 11 112 12 select * from t2; a b 1 1 2 2 3 13 4 14 5 15 6 6 7 7 8 8 9 9 drop table t1,t2; CREATE TABLE t2 ( NEXT_T BIGINT NOT NULL PRIMARY KEY) ENGINE=MEMORY; CREATE TABLE t1 ( B_ID INTEGER NOT NULL PRIMARY KEY) ENGINE=MyISAM; SET AUTOCOMMIT=0; INSERT INTO t1 ( B_ID ) VALUES ( 1 ); INSERT INTO t2 ( NEXT_T ) VALUES ( 1 ); ROLLBACK; Warnings: Warning 1196 Some non-transactional changed tables couldn't be rolled back SELECT * FROM t1; B_ID 1 drop table t1,t2; create table t1 ( pk int primary key, parent int not null, child int not null, index (parent) ) engine = MyISAM; insert into t1 values (1,0,4), (2,1,3), (3,2,1), (4,1,2); select distinct parent,child from t1 order by parent; parent child 0 4 1 2 1 3 2 1 drop table t1; create table t1 (a int not null auto_increment primary key, b int, c int, key(c)) engine=MyISAM; create table t2 (a int not null auto_increment primary key, b int) ENGINE = MEMORY; insert into t1 (b) values (null),(null),(null),(null),(null),(null),(null); insert into t2 (a) select b from t1; insert into t1 (b) select b from t2; insert into t2 (a) select b from t1; insert into t1 (a) select b from t2; insert into t2 (a) select b from t1; insert into t1 (a) select b from t2; insert into t2 (a) select b from t1; insert into t1 (a) select b from t2; insert into t2 (a) select b from t1; insert into t1 (a) select b from t2; insert into t2 (a) select b from t1; insert into t1 (a) select b from t2; insert into t2 (a) select b from t1; insert into t1 (a) select b from t2; insert into t2 (a) select b from t1; insert into t1 (a) select b from t2; insert into t2 (a) select b from t1; insert into t1 (a) select b from t2; select count(*) from t1; count(*) 29267 explain select * from t1 where c between 1 and 2500; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range c c 5 NULL # Using index condition update t1 set c=a; explain select * from t1 where c between 1 and 2500; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range c c 5 NULL # Using index condition drop table t1,t2; create table t1 (id int primary key auto_increment, fk int, index index_fk (fk)) engine=MyISAM; insert into t1 (id) values (null),(null),(null),(null),(null); update t1 set fk=69 where fk is null order by id limit 1; SELECT * from t1; id fk 1 69 2 NULL 3 NULL 4 NULL 5 NULL drop table t1; create table t1 (a int not null, b int not null, key (a)) engine=MyISAM; insert into t1 values (1,1),(1,2),(1,3),(3,1),(3,2),(3,3),(3,1),(3,2),(3,3),(2,1),(2,2),(2,3); SET @tmp=0; update t1 set b=(@tmp:=@tmp+1) order by a; update t1 set b=99 where a=1 order by b asc limit 1; update t1 set b=100 where a=1 order by b desc limit 2; update t1 set a=a+10+b where a=1 order by b; select * from t1 order by a,b; a b 2 4 2 5 2 6 3 7 3 8 3 9 3 10 3 11 3 12 13 2 111 100 111 100 drop table t1; create table t1 ( c char(8) not null ) engine=MyISAM; insert into t1 values ('0'),('1'),('2'),('3'),('4'),('5'),('6'),('7'),('8'),('9'); insert into t1 values ('A'),('B'),('C'),('D'),('E'),('F'); alter table t1 add b char(8) not null; alter table t1 add a char(8) not null; alter table t1 add primary key (a,b,c); update t1 set a=c, b=c; create table t2 (c char(8) not null, b char(8) not null, a char(8) not null, primary key(a,b,c)) engine=MyISAM; insert into t2 select * from t1; delete t1,t2 from t2,t1 where t1.a<'B' and t2.b=t1.b; drop table t1,t2; SET AUTOCOMMIT=1; create table t1 (a integer auto_increment primary key) engine=MyISAM; insert into t1 (a) values (NULL),(NULL); truncate table t1; insert into t1 (a) values (NULL),(NULL); SELECT * from t1; a 1 2 drop table t1; CREATE TABLE t1 (col1 int(1))ENGINE=MyISAM; CREATE TABLE t2 (col1 int(1),stamp TIMESTAMP,INDEX stamp_idx (stamp))ENGINE=MyISAM; insert into t1 values (1),(2),(3); insert into t2 values (1, 20020204130000),(2, 20020204130000),(4,20020204310000 ),(5,20020204230000); Warnings: Warning 1265 Data truncated for column 'stamp' at row 3 SELECT col1 FROM t1 UNION SELECT col1 FROM t2 WHERE stamp < '20020204120000' GROUP BY col1; col1 1 2 3 4 drop table t1,t2; CREATE TABLE t1 ( `id` int(10) unsigned NOT NULL auto_increment, `id_object` int(10) unsigned default '0', `id_version` int(10) unsigned NOT NULL default '1', `label` varchar(100) NOT NULL default '', `description` text, PRIMARY KEY (`id`), KEY `id_object` (`id_object`), KEY `id_version` (`id_version`) ) ENGINE=MyISAM; INSERT INTO t1 VALUES("6", "3382", "9", "Test", NULL), ("7", "102", "5", "Le Pekin (Test)", NULL),("584", "1794", "4", "Test de resto", NULL),("837", "1822", "6", "Test 3", NULL),("1119", "3524", "1", "Societe Test", NULL),("1122", "3525", "1", "Fournisseur Test", NULL); CREATE TABLE t2 ( `id` int(10) unsigned NOT NULL auto_increment, `id_version` int(10) unsigned NOT NULL default '1', PRIMARY KEY (`id`), KEY `id_version` (`id_version`) ) ENGINE=MyISAM; INSERT INTO t2 VALUES("3524", "1"),("3525", "1"),("1794", "4"),("102", "5"),("1822", "6"),("3382", "9"); SELECT t2.id, t1.`label` FROM t2 INNER JOIN (SELECT t1.id_object as id_object FROM t1 WHERE t1.`label` LIKE '%test%') AS lbl ON (t2.id = lbl.id_object) INNER JOIN t1 ON (t2.id = t1.id_object); id label 3382 Test 102 Le Pekin (Test) 1794 Test de resto 1822 Test 3 3524 Societe Test 3525 Fournisseur Test drop table t1,t2; create table t1 (a int, b varchar(200), c text not null) checksum=1 engine=MyISAM; create table t2 (a int, b varchar(200), c text not null) checksum=0 engine=MyISAM; create table t3 (a int, b varchar(200), c varchar(200) not null) checksum=1 engine=MEMORY; create table t4 (a int, b varchar(200), c varchar(200) not null) checksum=0 engine=MEMORY; create table t5 (a int, b varchar(200), c text not null) checksum=1 engine=MyISAM; create table t6 (a int, b varchar(200), c text not null) checksum=0 engine=MyISAM; insert t1 values (1, "aaa", "bbb"), (NULL, "", "ccccc"), (0, NULL, ""); insert t2 select * from t1; insert t3 select * from t1; insert t4 select * from t1; insert t5 select * from t1; insert t6 select * from t1; checksum table t1, t2, t3, t4, t5, t6, t7 quick; Table Checksum test.t1 3442722830 test.t2 NULL test.t3 NULL test.t4 NULL test.t5 3442722830 test.t6 NULL test.t7 NULL Warnings: Error 1146 Table 'test.t7' doesn't exist checksum table t1, t2, t3, t4, t5, t6, t7; Table Checksum test.t1 3442722830 test.t2 3442722830 test.t3 3442722830 test.t4 3442722830 test.t5 3442722830 test.t6 3442722830 test.t7 NULL Warnings: Error 1146 Table 'test.t7' doesn't exist checksum table t1, t2, t3, t4, t5, t6, t7 extended; Table Checksum test.t1 3442722830 test.t2 3442722830 test.t3 3442722830 test.t4 3442722830 test.t5 3442722830 test.t6 3442722830 test.t7 NULL Warnings: Error 1146 Table 'test.t7' doesn't exist drop table t1,t2,t3, t4, t5, t6; create table t1 (id int, name char(10) not null, name2 char(10) not null) engine=MyISAM; insert into t1 values(1,'first','fff'),(2,'second','sss'),(3,'third','ttt'); select trim(name2) from t1 union all select trim(name) from t1 union all select trim(id) from t1; trim(name2) fff sss ttt first second third 1 2 3 drop table t1; create table t1 (a int) engine=MyISAM; create table t2 like t1; show create table t2; Table Create Table t2 CREATE TABLE `t2` ( `a` int(11) DEFAULT NULL ) ENGINE=MyISAM DEFAULT CHARSET=latin1 drop table t1,t2; flush status; show status like "binlog_cache_use"; Variable_name Value Binlog_cache_use 0 show status like "binlog_cache_disk_use"; Variable_name Value Binlog_cache_disk_use 0 create table t1 (a int) engine=MyISAM; show status like "binlog_cache_use"; Variable_name Value Binlog_cache_use 0 show status like "binlog_cache_disk_use"; Variable_name Value Binlog_cache_disk_use 0 begin; delete from t1; commit; show status like "binlog_cache_use"; Variable_name Value Binlog_cache_use 0 show status like "binlog_cache_disk_use"; Variable_name Value Binlog_cache_disk_use 0 drop table t1; create table t1 (c char(10), index (c,c)) engine=MyISAM; ERROR 42S21: Duplicate column name 'c' create table t1 (c1 char(10), c2 char(10), index (c1,c2,c1)) engine=MyISAM; ERROR 42S21: Duplicate column name 'c1' create table t1 (c1 char(10), c2 char(10), index (c1,c1,c2)) engine=MyISAM; ERROR 42S21: Duplicate column name 'c1' create table t1 (c1 char(10), c2 char(10), index (c2,c1,c1)) engine=MyISAM; ERROR 42S21: Duplicate column name 'c1' create table t1 (c1 char(10), c2 char(10)) engine=MyISAM; 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(a int(1) , b int(1)) engine=MyISAM; insert into t1 values ('1111', '3333'); select distinct concat(a, b) from t1; concat(a, b) 11113333 drop table t1; create temporary table t1 (a int) engine=MyISAM; insert into t1 values (4711); truncate t1; insert into t1 values (42); select * from t1; a 42 drop table t1; create table t1 (a int) engine=MyISAM; insert into t1 values (4711); truncate t1; insert into t1 values (42); select * from t1; a 42 drop table t1; create table t1 (a int not null, b int not null, c blob not null, d int not null, e int, primary key (a,b,c(255),d)) engine=MyISAM; insert into t1 values (2,2,"b",2,2),(1,1,"a",1,1),(3,3,"ab",3,3); select * from t1 order by a,b,c,d; a b c d e 1 1 a 1 1 2 2 b 2 2 3 3 ab 3 3 explain select * from t1 order by a,b,c,d; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ALL NULL NULL NULL NULL 3 Using filesort drop table t1; create table t1 (a char(1), b char(1), key(a, b)) engine=MyISAM; insert into t1 values ('8', '6'), ('4', '7'); select min(a) from t1; min(a) 4 select min(b) from t1 where a='8'; min(b) 6 drop table t1; create table t1 (x bigint unsigned not null primary key) engine=MyISAM; insert into t1(x) values (0xfffffffffffffff0),(0xfffffffffffffff1); select * from t1; x 18446744073709551600 18446744073709551601 select count(*) from t1 where x>0; count(*) 2 select count(*) from t1 where x=0; count(*) 0 select count(*) from t1 where x<0; count(*) 0 select count(*) from t1 where x < -16; count(*) 0 select count(*) from t1 where x = -16; count(*) 0 explain select count(*) from t1 where x > -16; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 index PRIMARY PRIMARY 8 NULL 2 Using where; Using index select count(*) from t1 where x > -16; count(*) 2 select * from t1 where x > -16; x 18446744073709551600 18446744073709551601 select count(*) from t1 where x = 18446744073709551601; count(*) 1 drop table t1; set storage_engine=MyISAM; drop table if exists t1,t2,t3; --- Testing varchar --- --- Testing varchar --- create table t1 (v varchar(10), c char(10), t text); insert into t1 values('+ ', '+ ', '+ '); set @a=repeat(' ',20); insert into t1 values (concat('+',@a),concat('+',@a),concat('+',@a)); Warnings: Note 1265 Data truncated for column 'v' at row 1 select concat('*',v,'*',c,'*',t,'*') from t1; concat('*',v,'*',c,'*',t,'*') *+ *+*+ * *+ *+*+ * show create table t1; Table Create Table t1 CREATE TABLE `t1` ( `v` varchar(10) DEFAULT NULL, `c` char(10) DEFAULT NULL, `t` text ) ENGINE=MyISAM DEFAULT CHARSET=latin1 create table t2 like t1; show create table t2; Table Create Table t2 CREATE TABLE `t2` ( `v` varchar(10) DEFAULT NULL, `c` char(10) DEFAULT NULL, `t` text ) ENGINE=MyISAM DEFAULT CHARSET=latin1 create table t3 select * from t1; show create table t3; Table Create Table t3 CREATE TABLE `t3` ( `v` varchar(10) DEFAULT NULL, `c` char(10) DEFAULT NULL, `t` text ) ENGINE=MyISAM DEFAULT CHARSET=latin1 alter table t1 modify c varchar(10); show create table t1; Table Create Table t1 CREATE TABLE `t1` ( `v` varchar(10) DEFAULT NULL, `c` varchar(10) DEFAULT NULL, `t` text ) ENGINE=MyISAM DEFAULT CHARSET=latin1 alter table t1 modify v char(10); show create table t1; Table Create Table t1 CREATE TABLE `t1` ( `v` char(10) DEFAULT NULL, `c` varchar(10) DEFAULT NULL, `t` text ) ENGINE=MyISAM DEFAULT CHARSET=latin1 alter table t1 modify t varchar(10); Warnings: Note 1265 Data truncated for column 't' at row 2 show create table t1; Table Create Table t1 CREATE TABLE `t1` ( `v` char(10) DEFAULT NULL, `c` varchar(10) DEFAULT NULL, `t` varchar(10) DEFAULT NULL ) ENGINE=MyISAM DEFAULT CHARSET=latin1 select concat('*',v,'*',c,'*',t,'*') from t1; concat('*',v,'*',c,'*',t,'*') *+*+*+ * *+*+*+ * drop table t1,t2,t3; create table t1 (v varchar(10), c char(10), t text, key(v), key(c), key(t(10))); show create table t1; Table Create Table t1 CREATE TABLE `t1` ( `v` varchar(10) DEFAULT NULL, `c` char(10) DEFAULT NULL, `t` text, KEY `v` (`v`), KEY `c` (`c`), KEY `t` (`t`(10)) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 select count(*) from t1; count(*) 270 insert into t1 values(concat('a',char(1)),concat('a',char(1)),concat('a',char(1))); select count(*) from t1 where v='a'; count(*) 10 select count(*) from t1 where c='a'; count(*) 10 select count(*) from t1 where t='a'; count(*) 10 select count(*) from t1 where v='a '; count(*) 10 select count(*) from t1 where c='a '; count(*) 10 select count(*) from t1 where t='a '; count(*) 10 select count(*) from t1 where v between 'a' and 'a '; count(*) 10 select count(*) from t1 where v between 'a' and 'a ' and v between 'a ' and 'b\n'; count(*) 10 select count(*) from t1 where v like 'a%'; count(*) 11 select count(*) from t1 where c like 'a%'; count(*) 11 select count(*) from t1 where t like 'a%'; count(*) 11 select count(*) from t1 where v like 'a %'; count(*) 9 explain select count(*) from t1 where v='a '; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref v v 13 const # Using where; Using index explain select count(*) from t1 where c='a '; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref c c 11 const # Using where; Using index explain select count(*) from t1 where t='a '; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref t t 13 const # Using where explain select count(*) from t1 where v like 'a%'; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range v v 13 NULL # Using where; Using index explain select count(*) from t1 where v between 'a' and 'a '; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref v v 13 const # Using where; Using index explain select count(*) from t1 where v between 'a' and 'a ' and v between 'a ' and 'b\n'; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref v v 13 const # Using where; Using index alter table t1 add unique(v); ERROR 23000: Duplicate entry '{ ' for key 'v_2' alter table t1 add key(v); Warnings: Note 1831 Duplicate index `v_2`. This is deprecated and will be disallowed in a future release. select concat('*',v,'*',c,'*',t,'*') as qq from t1 where v='a'; qq *a*a*a* *a *a*a * *a *a*a * *a *a*a * *a *a*a * *a *a*a * *a *a*a * *a *a*a * *a *a*a * *a *a*a * explain select * from t1 where v='a'; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref v,v_2 # 13 const # # select v,count(*) from t1 group by v limit 10; v count(*) a 1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 select v,count(t) from t1 group by v limit 10; v count(t) a 1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 select v,count(c) from t1 group by v limit 10; v count(c) a 1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 select sql_big_result v,count(t) from t1 group by v limit 10; v count(t) a 1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 select sql_big_result v,count(c) from t1 group by v limit 10; v count(c) a 1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 select c,count(*) from t1 group by c limit 10; c count(*) a 1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 select c,count(t) from t1 group by c limit 10; c count(t) a 1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 select sql_big_result c,count(t) from t1 group by c limit 10; c count(t) a 1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 select t,count(*) from t1 group by t limit 10; t count(*) a 1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 select t,count(t) from t1 group by t limit 10; t count(t) a 1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 select sql_big_result t,count(t) from t1 group by t limit 10; t count(t) a 1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 alter table t1 modify v varchar(300), drop key v, drop key v_2, add key v (v); show create table t1; Table Create Table t1 CREATE TABLE `t1` ( `v` varchar(300) DEFAULT NULL, `c` char(10) DEFAULT NULL, `t` text, KEY `c` (`c`), KEY `t` (`t`(10)), KEY `v` (`v`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 select count(*) from t1 where v='a'; count(*) 10 select count(*) from t1 where v='a '; count(*) 10 select count(*) from t1 where v between 'a' and 'a '; count(*) 10 select count(*) from t1 where v between 'a' and 'a ' and v between 'a ' and 'b\n'; count(*) 10 select count(*) from t1 where v like 'a%'; count(*) 11 select count(*) from t1 where v like 'a %'; count(*) 9 explain select count(*) from t1 where v='a '; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref v v 303 const # Using where; Using index explain select count(*) from t1 where v like 'a%'; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range v v 303 NULL # Using where; Using index explain select count(*) from t1 where v between 'a' and 'a '; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref v v 303 const # Using where; Using index explain select count(*) from t1 where v between 'a' and 'a ' and v between 'a ' and 'b\n'; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref v v 303 const # Using where; Using index explain select * from t1 where v='a'; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref v v 303 const # # select v,count(*) from t1 group by v limit 10; v count(*) a 1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 select v,count(t) from t1 group by v limit 10; v count(t) a 1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 select sql_big_result v,count(t) from t1 group by v limit 10; v count(t) a 1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 alter table t1 drop key v, add key v (v(30)); show create table t1; Table Create Table t1 CREATE TABLE `t1` ( `v` varchar(300) DEFAULT NULL, `c` char(10) DEFAULT NULL, `t` text, KEY `c` (`c`), KEY `t` (`t`(10)), KEY `v` (`v`(30)) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 select count(*) from t1 where v='a'; count(*) 10 select count(*) from t1 where v='a '; count(*) 10 select count(*) from t1 where v between 'a' and 'a '; count(*) 10 select count(*) from t1 where v between 'a' and 'a ' and v between 'a ' and 'b\n'; count(*) 10 select count(*) from t1 where v like 'a%'; count(*) 11 select count(*) from t1 where v like 'a %'; count(*) 9 explain select count(*) from t1 where v='a '; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref v v 33 const # Using where explain select count(*) from t1 where v like 'a%'; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range v v 33 NULL # Using where explain select count(*) from t1 where v between 'a' and 'a '; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref v v 33 const # Using where explain select count(*) from t1 where v between 'a' and 'a ' and v between 'a ' and 'b\n'; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref v v 33 const # Using where explain select * from t1 where v='a'; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref v v 33 const # # select v,count(*) from t1 group by v limit 10; v count(*) a 1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 select v,count(t) from t1 group by v limit 10; v count(t) a 1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 select sql_big_result v,count(t) from t1 group by v limit 10; v count(t) a 1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 alter table t1 modify v varchar(600), drop key v, add key v (v); show create table t1; Table Create Table t1 CREATE TABLE `t1` ( `v` varchar(600) DEFAULT NULL, `c` char(10) DEFAULT NULL, `t` text, KEY `c` (`c`), KEY `t` (`t`(10)), KEY `v` (`v`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 select v,count(*) from t1 group by v limit 10; v count(*) a 1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 select v,count(t) from t1 group by v limit 10; v count(t) a 1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 select sql_big_result v,count(t) from t1 group by v limit 10; v count(t) a 1 a 10 b 10 c 10 d 10 e 10 f 10 g 10 h 10 i 10 drop table t1; create table t1 (a char(10), unique (a)); insert into t1 values ('a '); insert into t1 values ('a '); ERROR 23000: Duplicate entry 'a' for key 'a' alter table t1 modify a varchar(10); insert into t1 values ('a '),('a '),('a '),('a '); ERROR 23000: Duplicate entry 'a ' for key 'a' insert into t1 values ('a '); ERROR 23000: Duplicate entry 'a ' for key 'a' insert into t1 values ('a '); ERROR 23000: Duplicate entry 'a ' for key 'a' insert into t1 values ('a '); ERROR 23000: Duplicate entry 'a ' for key 'a' update t1 set a='a ' where a like 'a%'; select concat(a,'.') from t1; concat(a,'.') a . update t1 set a='abc ' where a like 'a '; select concat(a,'.') from t1; concat(a,'.') a . update t1 set a='a ' where a like 'a %'; select concat(a,'.') from t1; concat(a,'.') a . update t1 set a='a ' where a like 'a '; select concat(a,'.') from t1; concat(a,'.') a . drop table t1; create table t1 (v varchar(10), c char(10), t text, key(v(5)), key(c(5)), key(t(5))); show create table t1; Table Create Table t1 CREATE TABLE `t1` ( `v` varchar(10) DEFAULT NULL, `c` char(10) DEFAULT NULL, `t` text, KEY `v` (`v`(5)), KEY `c` (`c`(5)), KEY `t` (`t`(5)) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 drop table t1; create table t1 (v char(10) character set utf8); show create table t1; Table Create Table t1 CREATE TABLE `t1` ( `v` char(10) CHARACTER SET utf8 DEFAULT NULL ) ENGINE=MyISAM DEFAULT CHARSET=latin1 drop table t1; create table t1 (v varchar(10), c char(10)) row_format=fixed; show create table t1; Table Create Table t1 CREATE TABLE `t1` ( `v` varchar(10) DEFAULT NULL, `c` char(10) DEFAULT NULL ) ENGINE=MyISAM DEFAULT CHARSET=latin1 ROW_FORMAT=FIXED insert into t1 values('a','a'),('a ','a '); select concat('*',v,'*',c,'*') from t1; concat('*',v,'*',c,'*') *a*a* *a *a* drop table t1; create table t1 (v varchar(65530), key(v(10))); insert into t1 values(repeat('a',65530)); select length(v) from t1 where v=repeat('a',65530); length(v) 65530 drop table t1; create table t1(a int, b varchar(12), key ba(b, a)); insert into t1 values (1, 'A'), (20, NULL); explain select * from t1 where a=20 and b is null; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref ba ba 20 const,const 1 Using where; Using index select * from t1 where a=20 and b is null; a b 20 NULL drop table t1; create table t1 (v varchar(65530), key(v)); Warnings: Warning 1071 Specified key was too long; max key length is 1000 bytes drop table t1; create table t1 (v varchar(65536)); Warnings: Note 1246 Converting column 'v' from VARCHAR to TEXT show create table t1; Table Create Table t1 CREATE TABLE `t1` ( `v` mediumtext ) ENGINE=MyISAM DEFAULT CHARSET=latin1 drop table t1; create table t1 (v varchar(65530) character set utf8); Warnings: Note 1246 Converting column 'v' from VARCHAR to TEXT show create table t1; Table Create Table t1 CREATE TABLE `t1` ( `v` mediumtext CHARACTER SET utf8 ) ENGINE=MyISAM DEFAULT CHARSET=latin1 drop table t1; set storage_engine=MEMORY; create table t1 (v varchar(16384)) engine=MyISAM; drop table t1; create table t1 (a char(1), b char(1), key(a, b)) engine=MyISAM; insert into t1 values ('8', '6'), ('4', '7'); select min(a) from t1; min(a) 4 select min(b) from t1 where a='8'; min(b) 6 drop table t1; CREATE TABLE t1 ( `a` int(11) NOT NULL auto_increment, `b` int(11) default NULL,PRIMARY KEY (`a`),UNIQUE KEY `b` (`b`)) ENGINE=MyISAM; insert into t1 (b) values (1); replace into t1 (b) values (2), (1), (3); select * from t1; a b 3 1 2 2 4 3 truncate table t1; insert into t1 (b) values (1); replace into t1 (b) values (2); replace into t1 (b) values (1); replace into t1 (b) values (3); select * from t1; a b 3 1 2 2 4 3 drop table t1; create table t1 (rowid int not null auto_increment, val int not null,primary key (rowid), unique(val)) engine=MyISAM; replace into t1 (val) values ('1'),('2'); replace into t1 (val) values ('1'),('2'); insert into t1 (val) values ('1'),('2'); ERROR 23000: Duplicate entry '1' for key 'val' select * from t1; rowid val 3 1 4 2 drop table t1; CREATE TABLE t1 (GRADE DECIMAL(4) NOT NULL, PRIMARY KEY (GRADE)) ENGINE=MyISAM; INSERT INTO t1 (GRADE) VALUES (151),(252),(343); SELECT GRADE FROM t1 WHERE GRADE > 160 AND GRADE < 300; GRADE 252 SELECT GRADE FROM t1 WHERE GRADE= 151; GRADE 151 DROP TABLE t1; create table t1 (f1 varchar(10), f2 varchar(10), primary key (f1,f2)) engine=MyISAM; create table t2 (f3 varchar(10), f4 varchar(10), key (f4)) engine=MyISAM; insert into t2 values ('aa','cc'); insert into t1 values ('aa','bb'),('aa','cc'); delete t1 from t1,t2 where f1=f3 and f4='cc'; select * from t1; f1 f2 drop table t1,t2; create table t1(a int not null, b int, c int, d int, primary key(a)) engine=MyISAM; insert into t1(a) values (1),(2),(3); commit; set autocommit = 0; update t1 set b = 5 where a = 2; commit; create trigger t1t before insert on t1 for each row begin set NEW.b = NEW.a * 10 + 5, NEW.c = NEW.a / 10; end | set autocommit = 0; insert into t1(a) values (10),(20),(30),(40),(50),(60),(70),(80),(90),(100), (11),(21),(31),(41),(51),(61),(71),(81),(91),(101), (12),(22),(32),(42),(52),(62),(72),(82),(92),(102), (13),(23),(33),(43),(53),(63),(73),(83),(93),(103), (14),(24),(34),(44),(54),(64),(74),(84),(94),(104); commit; commit; drop trigger t1t; drop table t1; create table t1(a int not null, b int, c int, d int, primary key(a)) engine=MyISAM; create table t2(a int not null, b int, c int, d int, primary key(a)) engine=MyISAM; create table t3(a int not null, b int, c int, d int, primary key(a)) engine=MyISAM; create table t4(a int not null, b int, c int, d int, primary key(a)) engine=MyISAM; create table t5(a int not null, b int, c int, d int, primary key(a)) engine=MyISAM; insert into t1(a) values (1),(2),(3); insert into t2(a) values (1),(2),(3); insert into t3(a) values (1),(2),(3); insert into t4(a) values (1),(2),(3); insert into t3(a) values (5),(7),(8); insert into t4(a) values (5),(7),(8); insert into t5(a) values (1),(2),(3),(4),(5),(6),(7),(8),(9),(10),(11),(12); create trigger t1t before insert on t1 for each row begin INSERT INTO t2 SET a = NEW.a; end | create trigger t2t before insert on t2 for each row begin DELETE FROM t3 WHERE a = NEW.a; end | create trigger t3t before delete on t3 for each row begin UPDATE t4 SET b = b + 1 WHERE a = OLD.a; end | create trigger t4t before update on t4 for each row begin UPDATE t5 SET b = b + 1 where a = NEW.a; end | commit; set autocommit = 0; update t1 set b = b + 5 where a = 1; update t2 set b = b + 5 where a = 1; update t3 set b = b + 5 where a = 1; update t4 set b = b + 5 where a = 1; insert into t5(a) values(20); commit; set autocommit = 0; insert into t1(a) values(7); insert into t2(a) values(8); delete from t2 where a = 3; update t4 set b = b + 1 where a = 3; commit; drop trigger t1t; drop trigger t2t; drop trigger t3t; drop trigger t4t; drop table t1, t2, t3, t4, t5; create table t1(a date) engine=MyISAM; create table t2(a date, key(a)) engine=MyISAM; insert into t1 values('2005-10-01'); insert into t2 values('2005-10-01'); select * from t1, t2 where t2.a between t1.a - interval 2 day and t1.a + interval 2 day; a a 2005-10-01 2005-10-01 drop table t1, t2; create table t1 (id int not null, f_id int not null, f int not null, primary key(f_id, id)) engine=MyISAM; create table t2 (id int not null,s_id int not null,s varchar(200), primary key(id)) engine=MyISAM; INSERT INTO t1 VALUES (8, 1, 3); INSERT INTO t1 VALUES (1, 2, 1); INSERT INTO t2 VALUES (1, 0, ''); INSERT INTO t2 VALUES (8, 1, ''); commit; DELETE ml.* FROM t1 AS ml LEFT JOIN t2 AS mm ON (mm.id=ml.id) WHERE mm.id IS NULL; select ml.* from t1 as ml left join t2 as mm on (mm.id=ml.id) where mm.id is null lock in share mode; id f_id f drop table t1,t2; create table t1(a int not null, b int, primary key(a)) engine=MyISAM; insert into t1 values(1,1),(2,2),(3,1),(4,2),(5,1),(6,2),(7,3); commit; set autocommit = 0; SET SESSION TRANSACTION ISOLATION LEVEL READ COMMITTED; update t1 set b = 5 where b = 1; set autocommit = 0; SET SESSION TRANSACTION ISOLATION LEVEL READ COMMITTED; select * from t1 where a = 7 and b = 3 for update; a b 7 3 commit; commit; drop table t1; CREATE TABLE t1 ( a int ) ENGINE=MyISAM; BEGIN; INSERT INTO t1 VALUES (1); OPTIMIZE TABLE t1; Table Op Msg_type Msg_text test.t1 optimize status OK DROP TABLE t1;