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 a.device_id
, a.university
,count(b.question_id) as question_cnt
,count(if(b.result= 'right',b.question_id,null)) as right_qusetion_cnt
from
( select *
from user_profile
where university = '复旦大学'
)
a
left join
(
select *
from question_practice_detail
where substring(date,1,7)='2021-08'
)b on a.device_id=b.device_id
group by a.device_id, a.university
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