SQL Server存儲過程，在CASE子句內的Else語句中返回多個值

Question

我想在where子句中使用CASE和IN子句

• 當用戶狀態= 1時，CASE應該返回1
• 當用戶狀態= 2時，CASE應該返回2
• 當用戶狀態= 3時，CASE應該返回3
• 當User.Status = NULL時，它將顯示狀態為1、2和3的所有用戶

但是下面的查詢拋出語法錯誤。

查詢：

SELECT *
FROM User
where isInternalUser = 0 and DeleteMark <> 1 and
User.Status IN 
(
   CASE @UserStatus          // case for UserStatus
       WHEN 0 THEN 0
       WHEN 1 THEN 1
       WHEN 2 THEN 2
       ELSE (0,1,2)           
    END                      
)

誰能幫我一個忙..

謝謝，Aneesh

Answer 1

嘗試不使用CASE語句，但檢查@UserStatus IS NULL是否@UserStatus IS NULL ：

SELECT *
FROM User
WHERE isInternalUser = 0 AND DeleteMark <> 1 AND (
    (@UserStatus IS NOT NULL AND Status = @UserStatus)
    OR (@UserStatus IS NULL AND Status IN (0, 1, 2))
)

Answer 2

User.Status IN 
(
    SELECT s FROM (
        SELECT 1 s union SELECT 2 s union SELECT 3 s
    ) a
    WHERE @UserStatus is null or @UserStatus = s
)