What are all of the users’ names?
select name from useracct
How many wrote reviews?
select count(*) from useracct where u_id in (select u_id from review)
How many did not write reviews?
select count(*) from useracct where u_id not in (select u_id from review)
List their names.
select name from useracct where u_id not in (select u_id from review)