如何在SQL Server中使用rownumber获取匹配数据？

Question

我是SQL Server的新手,我不知道怎么说这个问题.我觉得这可能会重演.如果您知道,请将其标记为重复.我将用数据解释我想要实现的目标

表数据 - sometable

ID  TKID    Status    DateTimeStamp            RunMin
-----------------------------------------------------
215  6      Start   2009-10-29 09:48:14.243    NULL
261  6      Stop    2009-10-30 10:05:16.460    1457
356  6      Start   2009-11-03 14:11:05.097    NULL
357  6      Stop    2009-11-03 15:20:05.133    1526
358  6      Start   2009-11-03 16:14:45.863    NULL
574  19     Start   2009-11-12 13:12:11.827    NULL
575  19     Stop    2009-11-12 13:47:23.077    35
543 259     Start   2009-11-12 09:01:24.013    NULL 
620 259     Stop    2009-11-14 11:25:30.177    NULL 
623 259     Start   2009-11-14 16:47:32.913    NULL 
720 352     Start   2009-11-18 17:47:38.637    NULL 
730 352     Stop    2009-11-19 08:22:28.317    874  
773 352     Start   2009-11-20 10:00:11.320    NULL 
778 352     Stop    2009-11-20 11:51:59.853    985  
812 352     Start   2009-11-20 17:51:35.640    NULL 
813 352     Stop    2009-11-20 17:53:52.373    987  
822 352     Start   2009-11-23 08:13:23.030    NULL 
823 352     Stop    2009-11-23 08:17:33.063    991  
901 352     Start   2009-12-01 10:50:16.547    NULL 
910 352     Stop    2009-12-01 10:50:54.200    991  

预期产量:

ID  TKID    Status    DateTimeStamp            RunMin      
-----------------------------------------------------
358  6      Start   2009-11-03 16:14:45.863    NULL     
623 259     Start   2009-11-14 16:47:32.913    NULL 

所以基本上我想得到具有start状态但没有stop状态的记录.

现在我尝试了什么..

我试着使用ROW_NUMBER下面的功能,

;with cte as 
(
    select 
       *,
       ROW_NUMBER() OVER (PARTITION BY tkid 
                          ORDER BY tkid, DateTimeStamp) AS rn
    from Prog_Timer
)
SELECT * 
FROM 
   (SELECT * 
    FROM cte
    WHERE TkID IN (SELECT TkID
                   FROM cte 
                   GROUP BY TkID
                   HAVING COUNT(*)% 2 = 1)
) as d

它给了我结果

然后尝试获取Odd计数的tkid,并且tkid得到了数据.

ID  TKID    Status    DateTimeStamp            RunMin
-----------------------------------------------------
215  6      Start   2009-10-29 09:48:14.243    NULL
261  6      Stop    2009-10-30 10:05:16.460    1457
356  6      Start   2009-11-03 14:11:05.097    NULL
357  6      Stop    2009-11-03 15:20:05.133    1526
358  6      Start   2009-11-03 16:14:45.863    NULL
543 259     Start   2009-11-12 09:01:24.013    NULL 
620 259     Stop    2009-11-14 11:25:30.177    NULL 
623 259     Start   2009-11-14 16:47:32.913    NULL 

我不知道如何只从这个输出中获取最后一行,每次tkid只选择最后一个开始行.我认为我的approch非常复杂.必须有简单的方法来获得我想要的东西.如果您有新方法,请随时发布.如果您有任何要添加到我现有查询的内容,请随时发布.如果有困惑,请随意评论.

Answer 1

如果您修改了ROW_NUMBER() PARTITIONto order by DateTimeStamp desc,那么tkid将给出每个的最新行rn=1,从而为您提供每个行的最新状态tkid.然后你只需要SELECT行rn = 1和其中的行Status = 'Start'来获得你想要的输出:

select * from
(select 
   *,
   ROW_NUMBER() OVER (PARTITION BY tkid order by DateTimeStamp desc) as rn
from Prog_Timer
)
T
where 
T.rn = 1 -- the latest status for each tkid 
and T.Status = 'Start' -- returns only started and not stopped timers
-- if timer is stopped, t.Status will be 'Stop' in the latest row