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
up.university,
qd.difficult_level,
round(count(qpd.id) / count(distinct qpd.device_id), 4) as avg_answer_cnt
from
user_profile up
join question_practice_detail qpd on qpd.device_id = up.device_id
join question_detail qd on qpd.question_id = qd.question_id
where
university in ('山东大学')
group by
up.university,
difficult_level
ORDER BY
qd.difficult_level;
