select user.id,user.name from user 
where user.id in(
   select userid,count(roleid) from 中间表
where count(roleid)>1 group by userid);

--等大牛

------解决方案--------------------

role--有多个角色时把加条件加上b.roleName in('普通','管理员')
SQL code
select * from  [user] as a where not exists(select 1 from [role]  as b where b.roleName in('普通','管理员') and  not exists(select 1 from 中间表 where userID=a.userID and roleID=b.roleID))

------解决方案--------------------
SQL code
select distinct a.name 
from [user] a inner join 中间表 b on a.id=b.userid
inner join [role] c on c.id=b.roleid
inner join [role] d on d.id=b.roleid
where c.roleName='普通' and d.roleName='管理员'