Oracle 分组排序取第一条

Oracle 分组排序取第一条

    select r.user_id,r.user_name,r.user_age,r.least_time
    from (select t.user_id,t.user_name,t.user_age,t.least_time,row_number() over(
        partition by t.user_id order by t.least_time )rn
        from t_user_login t
        where t.status=0)r
    where r.rn=1

over（partition by t.user_id）按照用户id分区

参考资料 http://www.cnblogs.com/lanzi/archive/2010/10/26/1861338.html