Question

在我的数据库中，我有以下三个表，其中列出了字段：

TablePS 

 aID 

TableAM 

 aID(pk)
 bID  

TableM 

 bID(pk)
 bName

如果我知道TablePS中的aID，我怎样才能在TableM中找到bName的值？我尝试了以下查询：

SELECT bName FROM TableM WHERE bID=
(SELECT TablePS.aID,TableAM.aID 
FROM TablePS 
INNER JOIN TableAM 
ON TablePS.aID= TableAM.aID)

Answer 1

select bName
from tableM
    inner join tableAM on tableM.bID = tableAM.bID
where
    aID = [value]

应该足够了。如果你需要加入表PS，那么

select bName
from tableM
    inner join tableAM on tableM.bID = tableAM.bID
    inner join tablePS on tableAM.aID = tablePS.aID

Answer 2

Select BName from TableM as M inner join TableAM as Am on M.bId=Am.bID
inner join TablePS as P on Am.Aid=P.Aid

Answer 3

SELECT k.bName 
FROM TablePS p 
     INNER JOIN TableAM m ON m.aID = p.aID
     INNER JOIN TableM k on k.bID = m.bID

Answer 4

如果您不想使用JOIN，那么可能就是这样。

我假设aId是INT类型，您可以更改。

declare @x as int = 10 --<<change to an id that you are searching for

 select bname from  TableM  where bid in 
            (
            select  bID from TableAM  
            where aID in 
                             (
                             select aID from TablePS where aId = @x
                             ) 
            )

根据参数连接表

4 个答案: