# 先对时间排序 # select u.name u_n ,c.name c_n ,l.date , # rank()over(partition by l.user_id order by l.date desc) as rn # from login l,user u,client c # where l.user_id=u.id and l.client_id= c.id ; # 再取出时间排第一的 select u_n,c_n,date from (select u.name u_n ,c.name c_n ,l.date , rank()over(partition by l.us...