SQL - Only include rows that have more than one in class

Question

Im trying to eliminate classes with only 1 pupil

Here is the result i have

Desired Result

I want only class c to show as it has more than one pupil

I believe its some way of using HAVING but i cant figure it out.

SELECT Pupil, class
FROM school

Answer 1

Using IN

select * 
from school
where class in (select class 
                from school 
                group by class 
                having count(distinct Pupil) > 1)