PHP MySQL多表联查SQL语句笔记
联系查询在mysql中是常用的，用来把多个用按一个指定的参数来查找我们想要的内容，下面只讲到了两个表，如果多表我们直接加多表即可。
简单方法
| 代码如下 | 复制代码 |
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SELECT * FROM table1 n, table2 i WHERE n.itemid = i.itemid |
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左连接
| 代码如下 | 复制代码 |
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select * from tab a left join tab1 b on a.id=b.id |
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右连接
| 代码如下 | 复制代码 |
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