我想将此选择的每个DeviceId & Id的最近天数限制为x:
SELECT DeviceId, Id, MAX(DateAndTime) as 'DateAndTime'
FROM EventAndMessage
GROUP BY DeviceId, Id
ORDER BY DateAndTime DESC`
结果示例:
DeviceId Id DateAndTime
00:11:22:33:44:55 00D330 2018-05-25 15:41:10.620
00:03:4F:00:10:94 027286 2018-05-11 09:23:26.927
00:03:4F:00:10:94 0351DE 2018-05-11 09:23:13.690
00:03:4F:00:10:94 0351DE 2018-05-11 09:23:09.747
00:03:4F:00:10:94 0351DE 2018-05-11 09:23:01.797
00:03:4F:00:10:94 0351C4 2018-05-11 09:22:47.633
在这个例子中,我想最多限制2个最年轻的记录。注意:2应该是我可以更改的参数。
正确的结果应该是:
DeviceId Id DateAndTime
00:11:22:33:44:55 00D330 2018-05-25 15:41:10.620
00:03:4F:00:10:94 027286 2018-05-11 09:23:26.927
00:03:4F:00:10:94 0351DE 2018-05-11 09:23:13.690
00:03:4F:00:10:94 0351DE 2018-05-11 09:23:09.747
00:03:4F:00:10:94 0351C4 2018-05-11 09:22:47.633
谢谢
https://stackoverflow.com/questions/50750738
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