drop table if exists t1;
create table t1 (a int check (a>0));
insert into t1 values (1);
insert into t1 values (0);
drop table t1;
create table t1 (a int, b int, check (a>b));
insert into t1 values (1,0);
insert into t1 values (0,1);
drop table t1;
create table t1 (a int ,b int, constraint abc check (a>b));
insert into t1 values (1,0);
insert into t1 values (0,1);
drop table t1;
create table t1 (a int null);
insert into t1 values (1),(NULL);
drop table t1;
create table t1 (a int null);
alter table t1 add constraint constraint_1 unique (a);
alter table t1 add constraint unique key_1(a);
Warnings:
Note	1831	Duplicate index 'key_1' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
alter table t1 add constraint constraint_2 unique key_2(a);
Warnings:
Note	1831	Duplicate index 'key_2' defined on the table 'test.t1'. This is deprecated and will be disallowed in a future release.
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `a` int(11) DEFAULT NULL,
  UNIQUE KEY `constraint_1` (`a`),
  UNIQUE KEY `key_1` (`a`),
  UNIQUE KEY `key_2` (`a`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
drop table if exists t_illegal;
create table t_illegal (a int, b int, check a>b);
ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'a>b)' at line 1
create table t_illegal (a int, b int, constraint abc check a>b);
ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'a>b)' at line 1
create table t_illegal (a int, b int, constraint abc);
ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near ')' at line 1
drop table if exists t_11714;
create table t_11714(a int, b int);
alter table t_11714 add constraint cons1;
ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '' at line 1
drop table t_11714;
CREATE TABLE t_illegal (col_1 INT CHECK something (whatever));
ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'something (whatever))' at line 1
CREATE TABLE t_illegal (col_1 INT CHECK something);
ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'something)' at line 1