ok, find user id who gives the rating 10
select t1.u_id from useracct as t1 join review as t2 on t1.u_id = t2.u_id where t2.rating = 10
find the name of the user who gives most reviews
select t1.name from useracct as t1 join review as t2 on t1.u_id = t2.u_id group by t2.u_id order by count ( * ) desc limit 1
find the name of the user who gives 1 rank
select t1.name from useracct as t1 join review as t2 on t1.u_id = t2.u_id where t2.rank = 1