本文介绍了检查两个“选择"是否相等的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
有没有办法检查两个(非平凡的)选择是否等效?
Is there a way to check if two (non-trivial) select are equivalent?
最初我希望两个选择之间有形式上的等价，但答案是proving-sql-query-equivalency阻止我.
Initially I was hoping for a formally equivalence between two selects, but the answers in proving-sql-query-equivalency stop me.
对于我的实际需要，我可以检查两个选择的(实际)结果是否相同.
For my actual need I can just check if the (actual) results of two selects are the same.
推荐答案
如果您想比较查询结果，请尝试以下操作:
If you want to compare the query results try the following:
(select * from query1 MINUS select * from query2)
UNION ALL
(select * from query2 MINUS select * from query1)
这将导致所有行仅由一个查询返回.
This will result in all rows that are returned by only one of the queries.
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