题解 | #北京大学或练题数大于2的学生ID#
北京大学或练题数大于2的学生ID
https://www.nowcoder.com/practice/b2b639586d89409b9c1fa82c083287dd
select distinct device_id
from
(select device_id,university,
#窗口函数在一行最后标注该id的总练习数
sum(if(question_id is not null,1,0)) over(partition by device_id)as cnt
from user_profile
left join question_practice_detail
using(device_id)
)t
where university='北京大学' or cnt >2
order by 1 desc
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