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
一群渣渣，这才是正确的写法
select a.device_id,
university,
count(question_id) as question_cnt,
sum(if(b.result = 'right',1,0)) as right_question_cnt
from user_profile a
left join question_practice_detail b on a.device_id = b.device_id and month(date)=8
group by a.device_id,university
having university = "复旦大学"
