SQL Server存储过程参数输出

Question

我有一个存储过程，为了这个问题的目的我大大缩小了，但实质上我需要帮助的是这个问题。

如果表xyz中的一行已更新，我需要将ID附加到对方并输出回调用应用程序。更新按预期工作，问题在于我构建输出@IPV_ID_Found的方式（请参阅代码底部的注释部分）。

@IPV_Status varchar (50), 
@IPV_ID_Found varchar(500) = 'A' OUTPUT 

IF (@IPV_Status ='closed') 
BEGIN 
UPDATE TEST_TBL 
SET 
    Status = 'xyz',   
WHERE     
    ID  = @IPV_ID 

    -- this works for one ID 
    SELECT @IPV_ID_Found = (CAST(@IPV_ID AS VARCHAR(500)))  

    -- this does not work for multiple IDs 
    SELECT @IPV_ID_Found = @IPV_ID_Found + (CAST(@IPV_ID AS VARCHAR(500))) + ',' 

    -- neither does this 
    SET @IPV_ID_Found = @IPV_ID_Found + (CAST(@IPV_ID AS VARCHAR(500))) + ',' 

    SELECT @IPV_ID_Found     
END 

Answer 1

看到的变化：

-- this does not work for multiple IDs 
    SELECT @IPV_ID_Found = @IPV_ID_Found + ',' + (CAST(@IPV_ID AS VARCHAR(500))) 

那么你将得到的值的连续清单，像1,2,3,4,5

但如果需要返回记录，那么你需要不输出参数，请改用表格变量：

declare @IPV_ID_Found table(Item varchar(500)) 

IF (@IPV_Status ='closed') 
BEGIN 
UPDATE TEST_TBL 
SET 
    Status = 'xyz',   
WHERE     
    ID  = @IPV_ID 

    -- this works for one ID 
    insert @IPV_ID_Found 
    VALUES (CAST(@IPV_ID AS VARCHAR(500)))  

    -- this does not work for multiple IDs 
    INSERT @IPV_ID_Found 
    VALUES (CAST(@IPV_ID AS VARCHAR(500))) 

    SELECT Item FROM @IPV_ID_Found     
END