How many assessment notes are there?
select count(*) from assessment_notes
Show me the last name of teachers that had assessment notes in record.
select t2.last_name from assessment_notes as t1 join teachers as t2 on t1.teacher_id = t2.teacher_id
Give me the texts of assessment notes that Schuster had.
select t1.text_of_notes from assessment_notes as t1 join teachers as t2 on t1.teacher_id = t2.teacher_id where t2.last_name = "Schuster"