sql 联合变量模糊查询

用来多表查询

set @tt = "xxxxxx%";
SELECT * from (
SELECT username, `password`,password2 FROM user1 where username LIKE @tt
UNION
SELECT username, `password`,password2 FROM user2 where username LIKE @tt
UNION
SELECT username, `password`,password2 FROM user3 where username LIKE @tt
UNION
SELECT username, `password`,password2 FROM user4 where username LIKE @tt
UNION
SELECT username, `password`,password2 FROM user5 where username LIKE @tt) tmp LIMIT 10