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drop table if exists t1,t2;
create table t1 (
col1 int not null auto_increment primary key,
col2 varchar(30) not null,
col3 varchar (20) not null,
col4 varchar(4) not null,
col5 enum('PENDING', 'ACTIVE', 'DISABLED') not null,
col6 int not null, to_be_deleted int);
insert into t1 values (2,4,3,5,"PENDING",1,7);
alter table t1
add column col4_5 varchar(20) not null after col4,
add column col7 varchar(30) not null after col5,
add column col8 datetime not null, drop column to_be_deleted,
change column col2 fourth varchar(30) not null after col3,
modify column col6 int not null first;
select * from t1;
col6 col1 col3 fourth col4 col4_5 col5 col7 col8
1 2 3 4 5 PENDING 0000-00-00 00:00:00
drop table t1;
create table t1 (bandID MEDIUMINT UNSIGNED NOT NULL PRIMARY KEY, payoutID SMALLINT UNSIGNED NOT NULL);
insert into t1 (bandID,payoutID) VALUES (1,6),(2,6),(3,4),(4,9),(5,10),(6,1),(7,12),(8,12);
alter table t1 add column new_col int, order by payoutid,bandid;
select * from t1;
bandID payoutID new_col
6 1 NULL
3 4 NULL
1 6 NULL
2 6 NULL
4 9 NULL
5 10 NULL
7 12 NULL
8 12 NULL
alter table t1 order by bandid,payoutid;
select * from t1;
bandID payoutID new_col
1 6 NULL
2 6 NULL
3 4 NULL
4 9 NULL
5 10 NULL
6 1 NULL
7 12 NULL
8 12 NULL
drop table t1;
CREATE TABLE t1 (
GROUP_ID int(10) unsigned DEFAULT '0' NOT NULL,
LANG_ID smallint(5) unsigned DEFAULT '0' NOT NULL,
NAME varchar(80) DEFAULT '' NOT NULL,
PRIMARY KEY (GROUP_ID,LANG_ID),
KEY NAME (NAME));
ALTER TABLE t1 CHANGE NAME NAME CHAR(80) not null;
SHOW FULL COLUMNS FROM t1;
Field Type Collation Null Key Default Extra Privileges Comment
GROUP_ID int(10) unsigned NULL PRI 0 select,insert,update,references
LANG_ID smallint(5) unsigned NULL PRI 0 select,insert,update,references
NAME char(80) latin1_swedish_ci MUL select,insert,update,references
DROP TABLE t1;
create table t1 (n int);
insert into t1 values(9),(3),(12),(10);
alter table t1 order by n;
select * from t1;
n
3
9
10
12
drop table t1;
CREATE TABLE t1 (
id int(11) unsigned NOT NULL default '0',
category_id tinyint(4) unsigned NOT NULL default '0',
type_id tinyint(4) unsigned NOT NULL default '0',
body text NOT NULL,
user_id int(11) unsigned NOT NULL default '0',
status enum('new','old') NOT NULL default 'new',
PRIMARY KEY (id)
) TYPE=MyISAM;
ALTER TABLE t1 ORDER BY t1.id, t1.status, t1.type_id, t1.user_id, t1.body;
DROP TABLE t1;
CREATE TABLE t1 (AnamneseId int(10) unsigned NOT NULL auto_increment,B BLOB,PRIMARY KEY (AnamneseId)) type=myisam;
insert into t1 values (null,"hello");
LOCK TABLES t1 WRITE;
ALTER TABLE t1 ADD Column new_col int not null;
UNLOCK TABLES;
OPTIMIZE TABLE t1;
Table Op Msg_type Msg_text
test.t1 optimize status OK
DROP TABLE t1;
create table t1 (n1 int not null, n2 int, n3 int, n4 float,
unique(n1),
key (n1, n2, n3, n4),
key (n2, n3, n4, n1),
key (n3, n4, n1, n2),
key (n4, n1, n2, n3) );
alter table t1 disable keys;
show keys from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment
t1 0 n1 1 n1 A 0 NULL NULL BTREE
t1 1 n1_2 1 n1 A NULL NULL NULL BTREE disabled
t1 1 n1_2 2 n2 A NULL NULL NULL YES BTREE disabled
t1 1 n1_2 3 n3 A NULL NULL NULL YES BTREE disabled
t1 1 n1_2 4 n4 A NULL NULL NULL YES BTREE disabled
t1 1 n2 1 n2 A NULL NULL NULL YES BTREE disabled
t1 1 n2 2 n3 A NULL NULL NULL YES BTREE disabled
t1 1 n2 3 n4 A NULL NULL NULL YES BTREE disabled
t1 1 n2 4 n1 A NULL NULL NULL BTREE disabled
t1 1 n3 1 n3 A NULL NULL NULL YES BTREE disabled
t1 1 n3 2 n4 A NULL NULL NULL YES BTREE disabled
t1 1 n3 3 n1 A NULL NULL NULL BTREE disabled
t1 1 n3 4 n2 A NULL NULL NULL YES BTREE disabled
t1 1 n4 1 n4 A NULL NULL NULL YES BTREE disabled
t1 1 n4 2 n1 A NULL NULL NULL BTREE disabled
t1 1 n4 3 n2 A NULL NULL NULL YES BTREE disabled
t1 1 n4 4 n3 A NULL NULL NULL YES BTREE disabled
insert into t1 values(10,RAND()*1000,RAND()*1000,RAND());
insert into t1 values(9,RAND()*1000,RAND()*1000,RAND());
insert into t1 values(8,RAND()*1000,RAND()*1000,RAND());
insert into t1 values(7,RAND()*1000,RAND()*1000,RAND());
insert into t1 values(6,RAND()*1000,RAND()*1000,RAND());
insert into t1 values(5,RAND()*1000,RAND()*1000,RAND());
insert into t1 values(4,RAND()*1000,RAND()*1000,RAND());
insert into t1 values(3,RAND()*1000,RAND()*1000,RAND());
insert into t1 values(2,RAND()*1000,RAND()*1000,RAND());
insert into t1 values(1,RAND()*1000,RAND()*1000,RAND());
alter table t1 enable keys;
show keys from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment
t1 0 n1 1 n1 A 10 NULL NULL BTREE
t1 1 n1_2 1 n1 A 10 NULL NULL BTREE
t1 1 n1_2 2 n2 A 10 NULL NULL YES BTREE
t1 1 n1_2 3 n3 A 10 NULL NULL YES BTREE
t1 1 n1_2 4 n4 A 10 NULL NULL YES BTREE
t1 1 n2 1 n2 A 10 NULL NULL YES BTREE
t1 1 n2 2 n3 A 10 NULL NULL YES BTREE
t1 1 n2 3 n4 A 10 NULL NULL YES BTREE
t1 1 n2 4 n1 A 10 NULL NULL BTREE
t1 1 n3 1 n3 A 10 NULL NULL YES BTREE
t1 1 n3 2 n4 A 10 NULL NULL YES BTREE
t1 1 n3 3 n1 A 10 NULL NULL BTREE
t1 1 n3 4 n2 A 10 NULL NULL YES BTREE
t1 1 n4 1 n4 A 10 NULL NULL YES BTREE
t1 1 n4 2 n1 A 10 NULL NULL BTREE
t1 1 n4 3 n2 A 10 NULL NULL YES BTREE
t1 1 n4 4 n3 A 10 NULL NULL YES BTREE
drop table t1;
create table t1 (i int unsigned not null auto_increment primary key);
insert into t1 values (null),(null),(null),(null);
alter table t1 drop i,add i int unsigned not null auto_increment, drop primary key, add primary key (i);
select * from t1;
i
1
2
3
4
drop table t1;
create table t1 (i int unsigned not null auto_increment primary key);
alter table t1 rename t2;
alter table t2 rename t1, add c char(10) comment "no comment";
show columns from t1;
Field Type Null Key Default Extra
i int(10) unsigned PRI NULL auto_increment
c char(10) YES NULL
drop table t1;
create table t1 (a int, b int);
insert into t1 values(1,100), (2,100), (3, 100);
insert into t1 values(1,99), (2,99), (3, 99);
insert into t1 values(1,98), (2,98), (3, 98);
insert into t1 values(1,97), (2,97), (3, 97);
insert into t1 values(1,96), (2,96), (3, 96);
insert into t1 values(1,95), (2,95), (3, 95);
insert into t1 values(1,94), (2,94), (3, 94);
insert into t1 values(1,93), (2,93), (3, 93);
insert into t1 values(1,92), (2,92), (3, 92);
insert into t1 values(1,91), (2,91), (3, 91);
insert into t1 values(1,90), (2,90), (3, 90);
insert into t1 values(1,89), (2,89), (3, 89);
insert into t1 values(1,88), (2,88), (3, 88);
insert into t1 values(1,87), (2,87), (3, 87);
insert into t1 values(1,86), (2,86), (3, 86);
insert into t1 values(1,85), (2,85), (3, 85);
insert into t1 values(1,84), (2,84), (3, 84);
insert into t1 values(1,83), (2,83), (3, 83);
insert into t1 values(1,82), (2,82), (3, 82);
insert into t1 values(1,81), (2,81), (3, 81);
insert into t1 values(1,80), (2,80), (3, 80);
insert into t1 values(1,79), (2,79), (3, 79);
insert into t1 values(1,78), (2,78), (3, 78);
insert into t1 values(1,77), (2,77), (3, 77);
insert into t1 values(1,76), (2,76), (3, 76);
insert into t1 values(1,75), (2,75), (3, 75);
insert into t1 values(1,74), (2,74), (3, 74);
insert into t1 values(1,73), (2,73), (3, 73);
insert into t1 values(1,72), (2,72), (3, 72);
insert into t1 values(1,71), (2,71), (3, 71);
insert into t1 values(1,70), (2,70), (3, 70);
insert into t1 values(1,69), (2,69), (3, 69);
insert into t1 values(1,68), (2,68), (3, 68);
insert into t1 values(1,67), (2,67), (3, 67);
insert into t1 values(1,66), (2,66), (3, 66);
insert into t1 values(1,65), (2,65), (3, 65);
insert into t1 values(1,64), (2,64), (3, 64);
insert into t1 values(1,63), (2,63), (3, 63);
insert into t1 values(1,62), (2,62), (3, 62);
insert into t1 values(1,61), (2,61), (3, 61);
insert into t1 values(1,60), (2,60), (3, 60);
insert into t1 values(1,59), (2,59), (3, 59);
insert into t1 values(1,58), (2,58), (3, 58);
insert into t1 values(1,57), (2,57), (3, 57);
insert into t1 values(1,56), (2,56), (3, 56);
insert into t1 values(1,55), (2,55), (3, 55);
insert into t1 values(1,54), (2,54), (3, 54);
insert into t1 values(1,53), (2,53), (3, 53);
insert into t1 values(1,52), (2,52), (3, 52);
insert into t1 values(1,51), (2,51), (3, 51);
insert into t1 values(1,50), (2,50), (3, 50);
insert into t1 values(1,49), (2,49), (3, 49);
insert into t1 values(1,48), (2,48), (3, 48);
insert into t1 values(1,47), (2,47), (3, 47);
insert into t1 values(1,46), (2,46), (3, 46);
insert into t1 values(1,45), (2,45), (3, 45);
insert into t1 values(1,44), (2,44), (3, 44);
insert into t1 values(1,43), (2,43), (3, 43);
insert into t1 values(1,42), (2,42), (3, 42);
insert into t1 values(1,41), (2,41), (3, 41);
insert into t1 values(1,40), (2,40), (3, 40);
insert into t1 values(1,39), (2,39), (3, 39);
insert into t1 values(1,38), (2,38), (3, 38);
insert into t1 values(1,37), (2,37), (3, 37);
insert into t1 values(1,36), (2,36), (3, 36);
insert into t1 values(1,35), (2,35), (3, 35);
insert into t1 values(1,34), (2,34), (3, 34);
insert into t1 values(1,33), (2,33), (3, 33);
insert into t1 values(1,32), (2,32), (3, 32);
insert into t1 values(1,31), (2,31), (3, 31);
insert into t1 values(1,30), (2,30), (3, 30);
insert into t1 values(1,29), (2,29), (3, 29);
insert into t1 values(1,28), (2,28), (3, 28);
insert into t1 values(1,27), (2,27), (3, 27);
insert into t1 values(1,26), (2,26), (3, 26);
insert into t1 values(1,25), (2,25), (3, 25);
insert into t1 values(1,24), (2,24), (3, 24);
insert into t1 values(1,23), (2,23), (3, 23);
insert into t1 values(1,22), (2,22), (3, 22);
insert into t1 values(1,21), (2,21), (3, 21);
insert into t1 values(1,20), (2,20), (3, 20);
insert into t1 values(1,19), (2,19), (3, 19);
insert into t1 values(1,18), (2,18), (3, 18);
insert into t1 values(1,17), (2,17), (3, 17);
insert into t1 values(1,16), (2,16), (3, 16);
insert into t1 values(1,15), (2,15), (3, 15);
insert into t1 values(1,14), (2,14), (3, 14);
insert into t1 values(1,13), (2,13), (3, 13);
insert into t1 values(1,12), (2,12), (3, 12);
insert into t1 values(1,11), (2,11), (3, 11);
insert into t1 values(1,10), (2,10), (3, 10);
insert into t1 values(1,9), (2,9), (3, 9);
insert into t1 values(1,8), (2,8), (3, 8);
insert into t1 values(1,7), (2,7), (3, 7);
insert into t1 values(1,6), (2,6), (3, 6);
insert into t1 values(1,5), (2,5), (3, 5);
insert into t1 values(1,4), (2,4), (3, 4);
insert into t1 values(1,3), (2,3), (3, 3);
insert into t1 values(1,2), (2,2), (3, 2);
insert into t1 values(1,1), (2,1), (3, 1);
alter table t1 add unique (a,b), add key (b);
show keys from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment
t1 0 a 1 a A NULL NULL NULL YES BTREE
t1 0 a 2 b A NULL NULL NULL YES BTREE
t1 1 b 1 b A 100 NULL NULL YES BTREE
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
t1 0 a 1 a A 3 NULL NULL YES BTREE
t1 0 a 2 b A 300 NULL NULL YES BTREE
t1 1 b 1 b A 100 NULL NULL YES BTREE
drop table t1;
CREATE TABLE t1 (i int(10), index(i) );
ALTER TABLE t1 DISABLE KEYS;
INSERT DELAYED INTO t1 VALUES(1),(2),(3);
ALTER TABLE t1 ENABLE KEYS;
drop table t1;
set names koi8r;
create table t1 (a char(10) character set koi8r);
insert into t1 values ('ΤΕΣΤ');
select a,hex(a) from t1;
a hex(a)
ΤΕΣΤ D4C5D3D4
alter table t1 change a a char(10) character set cp1251;
select a,hex(a) from t1;
a hex(a)
ΤΕΣΤ F2E5F1F2
alter table t1 change a a char(10) binary;
select a,hex(a) from t1;
a hex(a)
ςερς F2E5F1F2
alter table t1 change a a char(10) character set cp1251;
select a,hex(a) from t1;
a hex(a)
ΤΕΣΤ F2E5F1F2
alter table t1 change a a char(10) character set koi8r;
select a,hex(a) from t1;
a hex(a)
ΤΕΣΤ D4C5D3D4
alter table t1 change a a varchar(10) character set cp1251;
select a,hex(a) from t1;
a hex(a)
ΤΕΣΤ F2E5F1F2
alter table t1 change a a char(10) character set koi8r;
select a,hex(a) from t1;
a hex(a)
ΤΕΣΤ D4C5D3D4
alter table t1 change a a text character set cp1251;
select a,hex(a) from t1;
a hex(a)
ΤΕΣΤ F2E5F1F2
alter table t1 change a a char(10) character set koi8r;
select a,hex(a) from t1;
a hex(a)
ΤΕΣΤ D4C5D3D4
drop table t1;
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