aabbcc hasn't got the point yet. But,
do you really think cyt's solution is better than that of #260300, in terms of performance? To my knowledge, join is much better than sub-query, especially when there is usable index.
闲来无事, 出道ORACLE SQL的题考考大家. 这是在下几个月前工作中遇到的问题, 看似简单, 其实不然.