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