oracle分組取每組第一條數據

oracle分組取每組第一條數據

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