计算两行之间的时间差 [英] Calculate the time difference between of two rows

问题描述

我有一个带有StartDate列的表，我想计算两个连续记录之间的时间差.

I have a table with column StartDate, I want to calculate the time difference between two consecutive record.

谢谢.

@ Mark Byers和@ Yahia，我将请求表作为requestId，开始日期

@ Mark Byers and @ Yahia, I have request table as requestId, startdate

requestId    startdate               
1            2011-10-16 13:15:56
2            2011-10-16 13:15:59
3            2011-10-16 13:15:59
4            2011-10-16 13:16:02
5            2011-10-16 13:18:07

，我想知道requestid 1和amp; amp;之间的时差是多少? 2、2& 3、3& 4，依此类推.我知道我将需要在表上进行自我联接，但是我在子句上的理解不正确.

and i want to know what is the time difference between requestid 1 & 2, 2 & 3, 3 & 4 and so on. i know i will need self join on table, but i am not getting correct on clause.

推荐答案

要达到您的要求，请尝试以下操作(从OP编辑后进行更新):

To achieve what you are asking try the following (UPDATE after edit from OP):

SELECT A.requestid, A.starttime, (B.starttime - A.starttime) AS timedifference
FROM MyTable A INNER JOIN MyTable B ON B.requestid = (A.requestid + 1)
ORDER BY A.requestid ASC

如果requestid不是连续的，则可以使用

IF requestid is not consecutive then you can use

SELECT A.requestid, A.starttime, (B.starttime - A.starttime) AS timedifference
FROM MyTable A CROSS JOIN MyTable B
WHERE B.requestid IN (SELECT MIN (C.requestid) FROM MyTable C WHERE C.requestid > A.requestid)
ORDER BY A.requestid ASC

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