select b.user_id,b.name,b.grade_num from (select a.user_id,a.name,a.grade_num,rank()over(order by a.grade_num desc) ranking from (select user_id,user.name,sum(case when type='add' then grade_num else (grade_num)*(-1) end) grade_num from grade_info join user on user.id=grade_info.user_id group by use...