题解：

• 由gpa最低，知： min(gpa)
• 由每个学校，知：order by university

• 法一：

select b.device_id,a.university,a.gpa
from user_profile as b,
(select device_id,university,min(gpa) gpa from user_profile
	group by university) as a 
where a.university=b.university and a.gpa=b.gpa
order by a.university

• 法二：

select device_id,university,gpa
from user_profile u
where gpa=(select min(gpa) from user_profile where university=u.university )
order by university