题解 | #统计每个用户的平均刷题数#
统计每个用户的平均刷题数
https://www.nowcoder.com/practice/f4714f7529404679b7f8909c96299ac4
select
university,
difficult_level,
round(count(q.question_id)/count(distinct q.question_id),4) as avg_answer_cnt
from user_profile u
inner join question_practice_detail q
on u.device_id = q.device_id
inner join question_detail qi
on q.question_id = qi.question_id
group by university, difficult_level
having university ='山东大学';
