How many assessment notes are there?
select count(*) from assessment_notes
How many does each student have?
select student_id, count(*) from assessment_notes group by student_id
Give me the id and first name of the student with the largest number of them.
select t1.student_id, t2.first_name from assessment_notes as t1 join students as t2 on t1.student_id = t2.student_id group by t1.student_id order by count(*) desc limit 1