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mysql三表连接查询问题

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Jun 23, 2016 pm 02:19 PM

三表左连接查询，为何会出现重复数据，有木有大神讲解一下原因啦啦啦啦！比如现在我单独查询有九条记录，但是还需要其他附属表的字段，结果连接查询出现重复数据，总数也是九条，这是神马情况啊？

回复讨论(解决方案)

这要看你的sql指令是如何写的
还有就是重复的数据来自哪个表？

左链接的结果中必然包含左表的全部符合条件的记录

贴出表的结构，贴出写的sql。

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