Question

我遇到了一个问题，因为我试图在内连接中进行显式连接，我试图从另一个表中选择某些值。

我的SQL：

SELECT A.OrderID
     , A.ItemID
     , A.Line
     , B.LID
     , B.Quantity 
FROM Sales A 
INNER JOIN (SELECT X.OrderID
                 , X.Line
                 , SUM(X.Quantity) AS Quantity
                 , X.DestinationID
                 , X.SerialNum 
            FROM SalesDetail X 
            WHERE X.OrderID = A.OrderID 
            GROUP BY X.OrderID, X.Line, X.DestinationID, X.SerialNum
           ) AS C
            ON A.Line = C.Line 
           AND B.Quantity = C.Quantity 
           AND B.SerialNum = C.SerialNum
INNER JOIN SalesContents B 
            ON A.OrderID = B.OrderID 
           AND A.ItemID = B.ItemID
WHERE A.OrderID = '12345'
AND  A.ItemID = 'ABC123';

现在我可以删除X表中的WHERE子句并在内连接中对其进行过滤，但我想在查询值时立即对其进行过滤。有没有办法重写这个语句，以便可以解决未绑定的标识符？

Answer 1

您无法在未定义的联接中引用别名。

如果你最后只使用子查询，那么你可以将它加入别名C，像......一样......

SELECT A.OrderID
     , A.ItemID
     , A.Line
     , B.LID
     , B.Quantity 
FROM Sales A 
INNER JOIN SalesContents B 
            ON A.OrderID = B.OrderID 
           AND A.ItemID = B.ItemID
INNER JOIN (SELECT X.OrderID
                 , X.Line
                 , SUM(X.Quantity) AS Quantity
                 , X.DestinationID
                 , X.SerialNum 
            FROM SalesDetail X 
            WHERE X.OrderID = A.OrderID 
            GROUP BY X.OrderID, X.Line, X.DestinationID, X.SerialNum
           ) AS C
            ON A.Line = C.Line 
           AND B.Quantity = C.Quantity 
           AND B.SerialNum = C.SerialNum
WHERE A.OrderID = '12345'
AND  A.ItemID = 'ABC123';

Answer 2

将子查询的WHERE子句移动到join的ON子句。别名“A”未在子查询中定义。

SELECT A.OrderID
     , A.ItemID
     , A.Line
     , B.LID
     , B.Quantity 
FROM Sales A 
INNER JOIN (SELECT X.OrderID
                 , X.Line
                 , SUM(X.Quantity) AS Quantity
                 , X.DestinationID
                 , X.SerialNum 
            FROM SalesDetail X 
            --WHERE X.OrderID = A.OrderID 
            GROUP BY X.OrderID, X.Line, X.DestinationID, X.SerialNum
           ) AS C
            ON A.Line = C.Line 
           AND C.OrderID = A.OrderID --<-- move the filter here
           AND B.Quantity = C.Quantity 
           AND B.SerialNum = C.SerialNum
INNER JOIN SalesContents B 
            ON A.OrderID = B.OrderID 
           AND A.ItemID = B.ItemID
WHERE A.OrderID = '12345'
-- you could also put it here instead
AND  A.ItemID = 'ABC123';

无法绑定TSQL多部分标识符（内部联接中的选择x表的显式连接）

2 个答案: