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急高分请问MySQL查询有关问题

Jun 13, 2016 pm 01:35 PM
join name

急!!!高分请教MySQL查询问题
现有表A和B
A表有一列bid允许为空,对应B表主键自增列
如果建视图的话,视图只会显示bid不为空的数据
A表bid为空的数据则显示不出
现在我想既有对应关系,又能显示A表bid为空的数据
只用一条语句,有办法实现么?该怎么写

SQL code
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例如:
表A
-----------------
id    bid    name
1     2      abc
2            def
3     1      ghi

表B
-----------------
bid   other
1     aaa
2     bbb

如果A的bid关联了B的bid
结果则为:
-----------------
id    bid    name   other
1     2      abc     aaa
3     1      ghi     bbb

以上
A表bid为空的列就没有了

现在我想要的结果则是:
-----------------
id    bid    name   other
1     2      abc     aaa
2            def
3     1      ghi     bbb

Copy after login


高分请教

------解决方案--------------------
去搜一下join left和join right我相信能够解决你的问题
------解决方案--------------------
select a.id,a.bid,a.name, b.other from A a left join B b on a.bid=b.bid;
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