What are the names of the users?
select name from useracct
How many wrote reviews?
select count(distinct t1.name) from useracct as t1 join review as t2 on t1.u_id = t2.u_id
List their names?
select distinct t1.name from useracct as t1 join review as t2 on t1.u_id = t2.u_id
Include the number of reviews written by each of them.
select t1.name, count(*) from useracct as t1 join review as t2 on t1.u_id = t2.u_id group by t2.u_id