How many schools are there?
select count ( school_code ) from department
How many professors are there in total?
select count ( * ) from professor
Which school has the most professors?
select t1.school_code from department as t1 join professor as t2 on t1.dept_code = t2.dept_code group by t1.school_code order by count ( * ) desc limit 1
How about the school with the least amount of professors?
select t1.school_code from department as t1 join professor as t2 on t1.dept_code = t2.dept_code group by t1.school_code order by count ( * ) limit 1
What departments does this school have?
select dept_name from department where school_code in ( select t1.school_code from department as t1 join professor as t2 on t1.dept_code = t2.dept_code group by t1.school_code order by count ( * ) limit 1 )