题解 | #出现三次以上相同积分的情况#

知识点：

1. group by + having子句

select number from (
select number, count(1) cnt from grade group by number 
having cnt >= 3) t1
order by number asc

2. 用row_number窗口函数也可以实现

select number from (
select number, row_number() over (partition by number) r from grade
) t1
where t1.r = 3
order by number asc