11题的理解

朋友你好，11题我理解的是，找到有两门及以上不及格课程的同学的学号。之后求其平均成绩。所以我的sql如下，你认为哪个理解符合题意一点呢？
```sql
select s.SId, s.Sname, avg(sc2.score)
from Student s
         inner join (
    select sc.SId from SC sc where sc.score < 60 group by sc.SId having count(1) >= 2
) as failed_two on s.SId = failed_two.SId
         inner join SC sc2 on s.SId = sc2.SId
group by 1, 2;
```