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(
count(q.question_id) / count(distinct q.device_id),
4
) as avg_answer_cnt
from
user_profile as u
inner join question_practice_detail as q on u.device_id = q.device_id
inner join question_detail as qd on q.question_id = qd.question_id
group by
university,difficult_level
