abba (Spitfire)
I tried this way this evening. But after several minutes I gave up. I find it difficult for me to get focused at home. Yeah, the performance could be bad when using sub-query, especially when the data volume is large.

By the way, I like to write join conditions in the JOIN clause, instead of WHERE. I feel that things are clearer in this way.

Thanks! I've certainly learnt something today.

2001-11-14 -04:00

回到话题: 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.

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