题解 | 浙大不同难度题目的正确率
浙大不同难度题目的正确率
https://www.nowcoder.com/practice/d8a4f7b1ded04948b5435a45f03ead8c
select
difficult_level,
sum(case when p2.result='right' then 1 else 0 end)/count(*) as correct_rate
from(
select device_id,university
from user_profile
where university='浙江大学'
) p1
join(
select device_id,question_id,result
from question_practice_detail
) p2
on p1.device_id = p2.device_id
join(
select question_id,difficult_level
from question_detail
) p3
on p2.question_id = p3.question_id
group by difficult_level
order by correct_rate
