Select 在 SQL 中加入 Select

Question

您好，我有一个 Select 内部连接语句，它看起来没问题，但我遇到了错误。这是我的查询

ALTER PROCEDURE [dbo].[POBalance]  @PONumber nvarchar(50)
AS BEGIN
Select( 
Select 
    A.Description,
    C.qty as POqty,
    B.QtyDelivered as PDQty, 
    case when A.partialflag ='false' 
    then '0'
    else
    A.qty  end as Balance,
    A.Unit,
    A.Unitprice,
    A.Partialflag 
from tblPOdetails as A

Inner Join  ( SELECT  id, SUM(Qty) AS QtyDelivered
                                    FROM         dbo.tblPDdetails
                                    WHERE     (PONo = @PONumber)
                                    GROUP BY id)as B On A.id = B.id   
Inner Join tblpodetailshistory as C on A.id =C.id

where A.PONo = @PONumber)
END

我遇到了这个错误。

Only one expression can be specified in the select list when the subquery is not introduced with EXISTS.

提前致谢。

Answer 1

您应该在外部 select 语句中包含列名和 From 关键字

ALTER PROCEDURE [dbo].[POBalance]  @PONumber nvarchar(50)
AS BEGIN
Select Description, POqty, PDQty, Balance, Unit, Unitprice, Partialflag  from ( 
Select 
    A.Description,
    C.qty as POqty,
    B.QtyDelivered as PDQty, 
    case when A.partialflag ='false' 
    then '0'
    else
    A.qty  end as Balance,
    A.Unit,
    A.Unitprice,
    A.Partialflag 
from tblPOdetails as A

Inner Join  ( SELECT  id, SUM(Qty) AS QtyDelivered
                                    FROM         dbo.tblPDdetails
                                    WHERE     (PONo = @PONumber)
                                    GROUP BY id)as B On A.id = B.id   
Inner Join tblpodetailshistory as C on A.id =C.id

where A.PONo = @PONumber)
END

其实不用写外层的select，可以改写成

ALTER PROCEDURE [dbo].[POBalance]  @PONumber nvarchar(50)
AS BEGIN

Select 
    A.Description,
    C.qty as POqty,
    B.QtyDelivered as PDQty, 
    case when A.partialflag ='false' 
    then '0'
    else
    A.qty  end as Balance,
    A.Unit,
    A.Unitprice,
    A.Partialflag 
from tblPOdetails as A

Inner Join  ( SELECT  id, SUM(Qty) AS QtyDelivered
                                    FROM         dbo.tblPDdetails
                                    WHERE     (PONo = @PONumber)
                                    GROUP BY id)as B On A.id = B.id   
Inner Join tblpodetailshistory as C on A.id =C.id

where A.PONo = @PONumber
END

Answer 2

问题出在您查询的开头，

Select( Select ....

删除初始 "Select (" 并重试查询。当你运行一个

Select (Select ..)

第二个 select 只能 return 一列（除非您连接 returned 数据）。

Select 在 SQL 中加入 Select

Select Inner Join Select in SQL

sql

inner-join