MySQL 左关联查询中两个以上数据表查询时,如何得到唯一匹配的数据
各位高手:
我在使用左关联查询时,要涉及到两个以上的数据表,虽然可以查询出数据,但是却出现多个匹配结果的情况,就好像是使用了普通的关联查询一样,请高手指教指教,不胜感激,谢谢了。
------解决方案--------------------
select *
from a left join b on a.id=b.id
left c on a.id=c.id
------解决方案--------------------
需要在后面加个where条件
------解决方案--------------------
left join ON条件
还有 where
------解决方案--------------------
ID 数据类型必须匹配

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