select * from test;
| no | time | name |
| 1001 | 20141226 | zhangsan |
| 1001 | 20141227 | lisi |
| 1002 | 20141228 | wangwu |
| 1002 | 20141229 | zhaoliu |
select * from (select rank() over(partition by documentno order by time desc) r,a.* from test
a) where r=1;
no
time name
----- ----------- ----------
1001 20141227 lisi
1002 20141229 zhaoliu
原文：http://blog.csdn.net/liwuyang2013/article/details/42174259