题解 | #所有用户对高难度题目的刷题数#
所有用户对高难度题目的刷题数
https://www.nowcoder.com/practice/e8b66c069376405bb7524b217c890b23
with cte as( select device_id,count(*) as cnt from question_practice_detail a left join question_detail b using(question_id) where difficult_level ='hard' group by device_id ) select device_id,ifnull(cnt,0) as question_cnt from user_profile a left join cte b using(device_id) order by question_cnt,device_id desc;