select username , email form member where username in (select username from ranking where score<=4 or score is null) order by username desc
这个语句如何用exsits或者not exsits表示呢?
还有一个问题就是
我想写一条语句...题目是
List the names of studios that have produced movies with more than one UK
actor in them. The output should contain no duplicates
....
非常急..在线等谢谢...
------解决方案--------------------
select username , email form member m
where exist (select 1 from ranking r on m.username =r.username where score<=4 or score is null) order by username desc