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select 1 与select */字段的区别

713660Jul 24 2009 — edited Jul 29 2009
各位好,我是一个应届毕业生,对数据库有一点喜欢
今天看到一条这样的语句 not exits (select 1 from 表名 where。。。 )
当时不知道select 1 出来的结果,在数据库中运行一下,知道其意思了。
当时觉得其实这条语句也可以这么写not exits (select * from 表名 where。。。 )

请问各位这两种select 1 与select * 有什么区别呢,是查询速度上的差别吗
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Locked on Aug 26 2009
Added on Jul 24 2009
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