yes
select shop_name from shop
now show me the shop which have devices in stock
select t2.shop_name from stock as t1 join shop as t2 on t1.shop_id = t2.shop_id group by t1.shop_id
now show me the shops that have more than one device in stock
select t2.shop_name from stock as t1 join shop as t2 on t1.shop_id = t2.shop_id group by t1.shop_id having count ( * ) > 1