动态ORDER BY子句包括计算列不起作用

Question

我有这样的语句：

DECLARE @OrderBy nvarchar(50) 
SELECT 
    t1.Forename, 
    t1.Surname, 
/** Calculcated Column Start **/ 
    (
    SELECT 
     (
     SELECT Count(FulfilledDelivery) FROM dbo.Deliveries d1 WHERE d1.UserID = t1.UserID 
    ) 
     - 
     (
     SELECT Count(CancelledDelivery) FROM dbo.Deliveries d1 WHERE d1.UserID = t1.UserID 
    ) 
    ) AS 'Deliveries' 
/** Calculcated Column End **/ 

FROM 
    TableName t1 
WHERE 
ORDER BY 
    CASE WHEN @OrderBy = 'Deliveries' THEN 'Deliveries' END DESC, 
    CASE WHEN @OrderBy = 'Forename' THEN t1.Forename END DESC, 
    CASE WHEN @OrderBy = 'Surname' THEN t1.Surname END DESC 
    END; 

基本上，这工作得很好，除了计算列“Deliveries”的排序依据子句中不起作用。我没有从我的SQL代码中得到任何错误，但是当我将@OrderBy参数设置为“Deliveries”时，它并没有通过calculcated列'Deliveries'排序。

如果我一条一条地删除动态订单，然后正常工作是这样的：

.... 
ORDER BY 
    'Deliveries' DESC; 

我怎样才能使它在动态版的工作？

Answer 1

是别名不能在ORDER BY访问，您可以使用CTE和计算列得到名字或你需要还

;WITH CTE T 
as 
(
SELECT 
    t1.Forename, 
    t1.Surname, 
/** Calculcated Column Start **/ 
    (
    SELECT 
     (
     SELECT Count(FulfilledDelivery) FROM dbo.Deliveries d1 WHERE d1.UserID = t1.UserID 
    ) 
     - 
     (
     SELECT Count(CancelledDelivery) FROM dbo.Deliveries d1 WHERE d1.UserID = t1.UserID 
    ) 
    ) AS 'Deliveries' 
/** Calculcated Column End **/ 

FROM 
    TableName t1 
) 
SELECT * FROM T 
ORDER BY 
    CASE WHEN @OrderBy = 'Deliveries' THEN T.Deliveries END DESC, 
    CASE WHEN @OrderBy = 'Forename' THEN T.Forename END DESC, 
    CASE WHEN @OrderBy = 'Surname' THEN T.Surname END DESC 
    END;