Which items have a rank?
select t1.title from item as t1 join review as t2 on t1.i_id = t2.i_id group by t2.i_id
Also include their IDs.
select t1.title, t1.i_id from item as t1 join review as t2 on t1.i_id = t2.i_id group by t2.i_id
Order them by average rank from highest to lowest.
select t1.title, t1.i_id from item as t1 join review as t2 on t1.i_id = t2.i_id group by t2.i_id order by avg(t2.rank)
What is the name and ID of the item that received the highest average rank?
select t1.title, t1.i_id from item as t1 join review as t2 on t1.i_id = t2.i_id group by t2.i_id order by avg(t2.rank) desc limit 1