SQL:获取每个唯一ID的最后一行

Question

我有一张桌子.我想获得每个独特的CoatingChambersID的最后一行.有24个独特的腔室,最后一行表示腔室处于最后状态的时间.

我可以得到一个如此独特的列表:

SELECT distinct CoatingChambersID, MAX(LastDT) as LastDT
  FROM [REO].[dbo].[CoatingChamberStateLogs] 
  group by CoatingChambersID

但我无法弄清楚如何将其加入到原始表中.

在此先感谢您的帮助!

CoatingChamberStateLogsID   CoatingChambersID   StartDT LastDT  IntervalMin  CoatingChamberStatesID 
1001712 1003    2017-01-24 23:09:29.4632108 2017-01-25 03:04:32.6758500 235.053543986667    1007    
1001713 1006    2017-01-24 23:09:29.4632108 2017-01-25 00:30:30.8478433 81.0230772083333    1007    
1001714 1015    2017-01-24 23:09:29.4632108 2017-01-25 04:21:33.7601011 312.071614838333    1007    
1001715 1024    2017-01-24 23:09:29.4632108 2017-01-31 04:43:21.5643016 8973.86835151333    1001    
1001716 1016    2017-01-24 23:09:29.4632108 2017-01-25 00:01:30.4200122 52.01594669 1006    
1001717 1017    2017-01-24 23:09:29.4632108 2017-01-24 23:15:29.8261612 6.00604917333333    1006    
1001718 1018    2017-01-24 23:09:29.4632108 2017-01-26 01:42:49.4040548 1593.3323474    1006    0   
1001719 1019    2017-01-24 23:09:29.4632108 2017-01-25 02:25:32.3047026 196.047358196667    1005    
1001720 1020    2017-01-24 23:09:29.4632108 2017-01-24 23:12:29.8009482 3.00562895666667    1007    
1001721 1022    2017-01-24 23:09:29.4632108 2017-01-25 02:52:32.5995144 223.052271726667    1007    
1001722 1023    2017-01-24 23:09:29.4632108 2017-01-25 03:05:32.9236594 236.057674143333    1007    
1001723 1002    2017-01-24 23:09:29.4475820 2017-01-25 02:14:32.1723891 185.045413451667    1001    
1001724 1004    2017-01-24 23:09:29.4632108 2017-01-25 00:39:31.0878194 90.02707681 1001    
1001725 1005    2017-01-24 23:09:29.4632108 2017-01-24 23:18:29.8783565 9.006919095 1001    

Answer 1

用途row_number():

select ccs.*
from (select ccs.*,
             row_number() over (partition by ccs.CoatingChambersID order by ccs.LastDt desc) as seqnum
      from [REO].[dbo].[CoatingChamberStateLogs] ccs
     ) ccs
where seqnum = 1;

使用select distinctwith group by几乎是不正确的.

另一种编写查询的有趣方式不需要子查询:

select top (1) with ties ccs.*
from [REO].[dbo].[CoatingChamberStateLogs] ccs
order by row_number() over (partition by ccs.CoatingChambersID order by ccs.LastDt desc);