如果U.LastName爲空，我如何讓Customer列忽略空格和逗號？

Question

我已經嘗試了幾種不同的方式，包括IF和CASE語句，但我不能完全看着辦吧......

SELECT  U.Login AS Login, U.LastName + ', ' + U.FirstName AS Customer, 
     cast(cast(IsNull(sum(O.BillAmount), 0) as decimal(19,5)) as float) AS 'Total Billing', 
     MIN(O.DateOrderCreated) AS 'First Order',       
     MAX(O.DateOrderCreated) AS 'Last Order' 
FROM Orders O 
INNER JOIN Store S ON S.StoreID = O.StoreID 
INNER JOIN fn_UserStores(@ActiveUserId,12) US ON S.StoreId = US.StoreId 
INNER JOIN Users U ON U.UserID = O.UserID 
WHERE  (O.IsCart = 0) AND (U.StatusID <> 2) AND (O.IsSaveForLater = 0) 
GROUP BY U.Login, U.LastName + ', ' + U.FirstName ORDER BY U.LastName + ', ' + U.FirstName 

Answer 1

您可以用CASE語句做到這一點：

SELECT Login, 
     Customer, 
     [Total Billing], 
     [First Order], 
     [Last Order] 
FROM 
(
    SELECT U.Login AS Login, 
      CASE WHEN U.LastName IS NOT NULL 
       THEN U.LastName + ', ' + U.FirstName 
       ELSE U.FirstName 
      END AS Customer, 
      cast(cast(IsNull(sum(O.BillAmount), 0) as decimal(19,5)) as float) AS 'Total Billing', 
      MIN(O.DateOrderCreated) AS 'First Order',       
      MAX(O.DateOrderCreated) AS 'Last Order' 
    FROM Orders O 
    INNER JOIN Store S ON S.StoreID = O.StoreID 
    INNER JOIN fn_UserStores(@ActiveUserId,12) US ON S.StoreId = US.StoreId 
    INNER JOIN Users U ON U.UserID = O.UserID 
    WHERE  (O.IsCart = 0) AND (U.StatusID <> 2) AND (O.IsSaveForLater = 0) 
) X 
GROUP BY Login, Customer 
ORDER BY Customer 

Answer 2

coalesce函數應該工作。更改此：

U.LastName + ', ' + U.FirstName AS Customer 

這樣：

coalesce(U.LastName + ', ', '') + U.FirstName AS Customer 

讓by子句的組中的類似變化。