一个sql语句 有三个以上的表,如A,B,C里面有不同的字段,但是有一个id三个表可以连接,我这样弄得 select * from A,B,C where A.d=B.id and B.id=C.id and A.id=c.id ................ 这样好多重复的记录啊,该咋修改一下呢?
------解决方案-------------------- Select * From A,B,C Where A.d=B.id and B.id=C.id
或者嵌套一个查询 select distinct column1,colunm2 from ( select * from A,B,C where A.id = B.id and B.id = C.id ) where ....
------解决方案-------------------- select * from A a inner join B b on a.id = b.id inner join C c on b.id =c.id where a.id = c.id
------解决方案--------------------
------解决方案--------------------
倒~~~按照你15楼的需求,应该用 Union 而不是 表连接
Select id, name Form A Union All Select id, name Form B Union All Select id, name Form C