Hello!  Can you provide me with a list of Instructor IDs for those who did not teach any courses?
select id from instructor where id not in ( select id from teaches )
Thank you!  Can you update that list with the professors' names?
select id, name from instructor where id not in ( select id from teaches )
Thank you!  Can you update that list to include the instructor names and which departments they are in?
select name, dept_name from instructor where id not in ( select id from teaches )