1.查询0，1，代表的状态\
SELECT hu.username,CASE WHEN hu.sex=0 THEN '男' WHEN hu.sex=1 THEN '女' END
FROM hj_user hu\
2.查询对个关联并拼接
select r.roleid,r.rolename,
(select group_concat(m.menuname separator ',' ) menuname
from hj_menu m ,hj_role_menu rm
where rm.roleid = r.roleid and rm.menuid = m.menuid ) menuname
from hj_role r
\