题解 | #统计每个学校各难度的用户平均刷题数#
统计每个学校各难度的用户平均刷题数
https://www.nowcoder.com/practice/5400df085a034f88b2e17941ab338ee8
select university,difficult_level,round(avg(avg_answer_cnt_1),4) as avg_answer_cnt 平均答题数
from
(select university,question_id,avg(t.answer_cnt) as avg_answer_cnt_1 不同学校不同类型题目的平均答题数
from
user_profile as u
join
(select device_id,question_id,count(*) as answer_cnt 不同人不同类型的答题数
from question_practice_detail group by device_id,question_id ) as ton u.device_id=t.device_id
group by university,question_id)as d
join question_detail as q on d.question_id=q.question_id
group by university,difficult_level #不同学校不同难度
