思路就是反过来想就简单了
最后一句这样写就意思明显 SELECT distinct name from (select name from zzxxz where score<=80)
select distinct name from zzxxz where name not in (select distinct name from zzxxz where score<=80)
查询每门课都大于80分的学生姓名
原文：http://www.cnblogs.com/zx-admin/p/5663927.html
