开窗函数处理 select t.id, t.name, t.grade_num from ( select u.id, u.name, sum(if (g.type = 'add', g.grade_num, - g.grade_num)) as grade_num, dense_rank() over ( order by sum(if (g.type = 'add', g.grade_num, - g.grade_num)) desc ) rk from user u left join grade_info g on u.id = g.user_id group by u.id, u.n...