题解 | 统计复旦用户8月练题情况
统计复旦用户8月练题情况
https://www.nowcoder.com/practice/53235096538a456b9220fce120c062b3
select
up.device_id,
up.university,
count(qpd.question_id) question_cnt,
sum(if(qpd.result = 'right', 1, 0)) right_question_cnt
# sum嵌套if达到条件求和的作用
from
user_profile up
left join question_practice_detail qpd on up.device_id = qpd.device_id
and left(qpd.date, 7) = '2021-08'
where
up.university = '复旦大学'
group by
1,
2
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