set @save_check_constraint=@@check_constraint_checks;
create table t1 (a int check(a>10), b int check (b > 20), constraint `min` check (a+b > 100), constraint `max` check (a+b <500)) engine=myisam;
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `a` int(11) DEFAULT NULL CHECK (`a` > 10),
  `b` int(11) DEFAULT NULL CHECK (`b` > 20),
  CONSTRAINT `min` CHECK (`a` + `b` > 100),
  CONSTRAINT `max` CHECK (`a` + `b` < 500)
) ENGINE=MyISAM DEFAULT CHARSET=latin1
insert into t1 values (100,100);
insert into t1 values (1,1);
ERROR 23000: CONSTRAINT `a` failed for `test`.`t1`
insert into t1 values (20,1);
ERROR 23000: CONSTRAINT `b` failed for `test`.`t1`
insert into t1 values (20,30);
ERROR 23000: CONSTRAINT `min` failed for `test`.`t1`
insert into t1 values (500,500);
ERROR 23000: CONSTRAINT `max` failed for `test`.`t1`
insert into t1 values (101,101),(102,102),(600,600),(103,103);
ERROR 23000: CONSTRAINT `max` failed for `test`.`t1`
select * from t1;
a	b
100	100
101	101
102	102
truncate table t1;
insert ignore into t1 values (101,101),(102,102),(600,600),(103,103);
Warnings:
Warning	4025	CONSTRAINT `max` failed for `test`.`t1`
select * from t1;
a	b
101	101
102	102
103	103
set check_constraint_checks=0;
truncate table t1;
insert into t1 values (101,101),(102,102),(600,600),(103,103);
select * from t1;
a	b
101	101
102	102
600	600
103	103
set check_constraint_checks=@save_check_constraint;
alter table t1 add c int default 0 check (c < 10);
ERROR 23000: CONSTRAINT `max` failed for table
set check_constraint_checks=0;
alter table t1 add c int default 0 check (c < 10);
alter table t1 add check (a+b+c < 500);
set check_constraint_checks=@save_check_constraint;
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `a` int(11) DEFAULT NULL CHECK (`a` > 10),
  `b` int(11) DEFAULT NULL CHECK (`b` > 20),
  `c` int(11) DEFAULT 0 CHECK (`c` < 10),
  CONSTRAINT `min` CHECK (`a` + `b` > 100),
  CONSTRAINT `max` CHECK (`a` + `b` < 500),
  CONSTRAINT `CONSTRAINT_1` CHECK (`a` + `b` + `c` < 500)
) ENGINE=MyISAM DEFAULT CHARSET=latin1
insert into t1 values(105,105,105);
ERROR 23000: CONSTRAINT `c` failed for `test`.`t1`
insert into t1 values(249,249,9);
ERROR 23000: CONSTRAINT `CONSTRAINT_1` failed for `test`.`t1`
insert into t1 values(105,105,9);
select * from t1;
a	b	c
101	101	0
102	102	0
600	600	0
103	103	0
105	105	9
create table t2 like t1;
show create table t2;
Table	Create Table
t2	CREATE TABLE `t2` (
  `a` int(11) DEFAULT NULL CHECK (`a` > 10),
  `b` int(11) DEFAULT NULL CHECK (`b` > 20),
  `c` int(11) DEFAULT 0 CHECK (`c` < 10),
  CONSTRAINT `min` CHECK (`a` + `b` > 100),
  CONSTRAINT `max` CHECK (`a` + `b` < 500),
  CONSTRAINT `CONSTRAINT_1` CHECK (`a` + `b` + `c` < 500)
) ENGINE=MyISAM DEFAULT CHARSET=latin1
alter table t2 drop constraint c;
ERROR 42000: Can't DROP CONSTRAINT `c`; check that it exists
alter table t2 drop constraint if exists c;
Warnings:
Note	1091	Can't DROP CONSTRAINT `c`; check that it exists
alter table t2 drop constraint min;
show create table t2;
Table	Create Table
t2	CREATE TABLE `t2` (
  `a` int(11) DEFAULT NULL CHECK (`a` > 10),
  `b` int(11) DEFAULT NULL CHECK (`b` > 20),
  `c` int(11) DEFAULT 0 CHECK (`c` < 10),
  CONSTRAINT `max` CHECK (`a` + `b` < 500),
  CONSTRAINT `CONSTRAINT_1` CHECK (`a` + `b` + `c` < 500)
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1,t2;
create or replace table t1 (a int, b int, constraint check (a>b));
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `a` int(11) DEFAULT NULL,
  `b` int(11) DEFAULT NULL,
  CONSTRAINT `CONSTRAINT_1` CHECK (`a` > `b`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1
create or replace table t1 (a int, b int,
constraint CONSTRAINT_1 check (a>1),
constraint check (b>1));
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `a` int(11) DEFAULT NULL,
  `b` int(11) DEFAULT NULL,
  CONSTRAINT `CONSTRAINT_1` CHECK (`a` > 1),
  CONSTRAINT `CONSTRAINT_2` CHECK (`b` > 1)
) ENGINE=MyISAM DEFAULT CHARSET=latin1
create or replace table t1 (a int, b int,
constraint CONSTRAINT_1 check (a>1),
constraint check (b>1),
constraint CONSTRAINT_2 check (a>b));
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `a` int(11) DEFAULT NULL,
  `b` int(11) DEFAULT NULL,
  CONSTRAINT `CONSTRAINT_1` CHECK (`a` > 1),
  CONSTRAINT `CONSTRAINT_3` CHECK (`b` > 1),
  CONSTRAINT `CONSTRAINT_2` CHECK (`a` > `b`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
create table t1(c1 int, c2 int as (c1 + 1), check (c2 > 2));
insert into t1(c1) values(1);
ERROR 23000: CONSTRAINT `CONSTRAINT_1` failed for `test`.`t1`
insert into t1(c1) values(2);
drop table t1;
create table t1 (a int, b int, check(a>0));
alter table t1 drop column a;
ERROR 42S22: Unknown column 'a' in 'CHECK'
drop table t1;
create table t1 (a int check (@b in (select user from mysql.user)));
ERROR HY000: Function or expression 'select ...' cannot be used in the CHECK clause of `a`
create table t1 (a int check (a > @b));
ERROR HY000: Function or expression '@b' cannot be used in the CHECK clause of `a`