题解 | #找出每个学校GPA最低的同学#

select user_profile.device_id,user_profile.university,user_profile.gpa
from(
    select university,min(gpa) as gpa
    from user_profile
    group by university) as t1 inner join user_profile
	#派生出来的表必须有别名
on t1.university = user_profile.university and user_profile.gpa = t1.gpa
order by t1.university asc