力扣数据库进阶50--No.1112题解

官方难度中等，体感偏简单，算是启蒙题。

这里采用窗口函数，分组排序取到学生的最高分成绩。

select student_id,course_id,grade
from 
    (select *,rank() over(partition by student_id order by grade desc,course_id) as rnk
    from Enrollments) as tmp
where rnk = 1
order by student_id