跟上一题差不多,多加了个case when #窗口函数 select t.user_id,u.name, grade from (select user_id,dense_rank() over(order by grade desc) rank1,grade from (select distinct user_id,sum(case when type='add' then grade_num when type='reduce' then -grade_num end) over(partition by user_id) grade from grade_info ) a) t,use...