MySQL一个字段做一对多关联

SELECT  * 
from t_user a ,t_role b
where b.role_id REGEXP concat('^',a.roles,'$')


select * from t_role b where b.role_id REGEXP (select concat('^',roles,'$') from t_user where user_id = 1)


以上两个SQL都是返回两条记录


数据表
insert into t_user(user_id,user_name,roles) values(1,'test','1|68');
insert into t_role(role_id,role_name) values(1,'role1'),(68,'role2'),(168,'role3');