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在写php语句中sql的写法有些混
- WBOYOriginal
- 2016-06-13 12:19:50839browse
在写php语句中sql的写法有点混
即where和having是否可以通用
------解决思路----------------------
where 是删选数据表的条件
having 是删选结果集的条件
经 where 删选后，结果集就可能会很小
having 只是再做一次筛选以挑出所需数据
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