行的时差

Question

我想获得多行之间的时差

  Sl_id   ID     ShortLeave               createddate

    15    8     2015-10-02 13:10:07   2015-02-11 16:08:01
    16    8     2015-10-02 14:05:07   2015-02-11 16:08:01

我需要按where Id=1获取短假差异过滤器。我试过了

SELECT  timediff(A.shortleave,B.shortleave) AS timedifference
FROM shortL A  JOIN shortL B ON B.id = A.id 
where A.Id=1
group by A.ID,A.ShortLeave ;

但我有两行

'00:00:00'
'00:55:00'

这是因为Sl_id。所以请帮助我如何获得多行的一行。

Answer 1

我更改了我的查询

SELECT  timediff(A.shortleave,B.shortleave) AS timedifference
FROM shortL A  JOIN shortL B ON B.id = A.id 
where A.Id=1
group by A.ID,A.ShortLeave order by timedifference desc limit 1;

通过这样做我总是得到最新专栏。在这里我只得到'00:55:00'，结果没问题。