mysql> create table user(id bigint(10), name varchar(20), qq varchar(10));
Query OK, 0 rows affected (0.06 sec)
mysql> alter table user add constraint u_idname unique(id,name);
Query OK, 0 rows affected (0.08 sec)
Records: 0 Duplicates: 0 Warnings: 0
mysql> insert into user values(1, "gcf","345346");
Query OK, 1 row affected (0.00 sec)
mysql> insert into user values(1, "gcf","345346");
ERROR 1062 (23000): Duplicate entry '1-gcf' for key 'u_idname'
mysql>insert into user values(2, "gcf","345346");
Query OK, 1 row affected (0.00 sec)