Question

我有一张如下表格

ID      status          message     set  
---------------------------------------
1       Completed       step1       1  
2       Completed       step2       1  
3       Failed          step3       1  
4       Completed       step1       2  
5       Completed       step2       2  
6       Failed          step3       2

对于每一组，如果步骤失败，我需要复制上一步并创建一个状态为＆＃34; New＆＃34;的新行。所以我的桌子需要看起来像

ID      status          message     set  
---------------------------------------
1       Completed       step1       1  
2       Completed       step2       1  
3       Failed          step3       1  
4       Completed       step1       2  
5       Completed       step2       2  
6       Failed          step3       2  
7       New             step2       1  
8       New             step2       2

有人可以帮我处理SQL查询吗？我一直试图用Lag和db_cursor写一些东西，但到目前为止还没有运气。我将继续努力，如果有人指出我正确的方向，那将是有帮助的。

Answer 1

我到达了下面的解决方案。

DECLARE @set INT,
        @id  INT

--create a temporary table collecting the set value for the rows with failed message

IF OBJECT_ID(N'tempdb.dbo.#failList') IS NOT NULL
DROP TABLE #failList
SELECT  set
INTO    #failList
FROM    my_table WITH (NOLOCK)
WHERE  status = 'Failed'
and message = 'step3'

--loop over the failList and match the step to get the previous row and duplicate it

WHILE EXISTS (SELECT TOP 1 1 FROM #failList)
BEGIN
SELECT TOP 1 @step = step
FROM    #failList

INSERT  INTO my_table (status, message, set)
SELECT  'New', message, set]
FROM    my_table d WITH (NOLOCK)
    WHERE   d.set = @set
    and message = 'step2'

DELETE FROM #failList WHERE set = @set      
END

SQL - 获取上一行并使用条件复制它

1 个答案: