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(qpd.question_id)/count(distinct qpd.device_id),4) as avg_answer_cnt
from question_practice_detail as qpd
left join
user_profile as up
on
up.device_id=qpd.device_id
left join
question_detail as qd
on
qd.question_id = qpd.question_id
group by university,difficult_level;
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