题解 | 找出每个学校GPA最低的同学

select
    device_id,
    university,
    gpa
from(select 	device_id ,university ,gpa ,row_number() over (partition by university
order by gpa) as r from user_profile) u_gra_min
where r=1

order by
    university

ROW_NUMBER() OVER ( PARTITION BY university -- 按大学分组 ORDER BY gpa -- 在每个大学内按 GPA 升序排序 ) AS r -- 将排名结果命名为 r

分组排序函数 ROW_NUMBER() OVER(

PARTITION BY A

ORBER BY B

)