求下表中,相同gsbm,dh,lljbh里jssj最大的N条表结构如下:
gsbm dh lljbh jssj1 1 1 2005-1-1 10:00:00
1 1 2 2005-1-1 10:00:001 1 1 2005-1-1 10:10:00
1 1 2 2005-1-1 10:10:001 1 1 2005-1-1 10:20:00
1 1 2 2005-1-1 10:20:002 2 1 2005-1-1 11:00:00
2 2 2 2005-1-1 11:00:002 2 1 2005-1-1 11:05:00
2 2 2 2005-1-1 11:05:00
gsbm dh lljbh jssj1 1 1 2005-1-1 10:00:00
1 1 2 2005-1-1 10:00:001 1 1 2005-1-1 10:10:00
1 1 2 2005-1-1 10:10:001 1 1 2005-1-1 10:20:00
1 1 2 2005-1-1 10:20:002 2 1 2005-1-1 11:00:00
2 2 2 2005-1-1 11:00:002 2 1 2005-1-1 11:05:00
2 2 2 2005-1-1 11:05:00
gsbm dh lljbh jssj ljll1 1 1 2005-1-1 10:00:00 0.1
1 1 2 2005-1-1 10:00:00 0.21 1 1 2005-1-1 10:10:00 0.3
1 1 2 2005-1-1 10:10:00 0.41 1 1 2005-1-1 10:20:00 0.5
1 1 2 2005-1-1 10:20:00 0.62 2 1 2005-1-1 11:00:00 0.1
2 2 2 2005-1-1 11:00:00 0.22 2 1 2005-1-1 11:05:00 0.3
2 2 2 2005-1-1 11:05:00 0.4本来想省点事,谁知让要求变了味,不好意思,这才是要求
select gsbm,dh,lljbh,max(jssj) from 表名 group by gsbm,dh,lljbh);