List the name of each item that received a rating.
select t1.title from item as t1 join review as t2 on t1.i_id = t2.i_id group by t2.i_id
Include the item ID as well.
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 items by decreasing average rating.
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.rating) desc
Which item had the highest? Include its ID as well.
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.rating) desc limit 1