Show the name of the shop that has the most kind of devices in stock.
create table shop (shop_name varchar, shop_id varchar, PRIMARY KEY (shop_name)); create table stock (shop_id varchar, PRIMARY KEY (shop_id))
select t2.shop_name from stock as t1 join shop as t2 on t1.shop_id = t2.shop_id group by t1.shop_id order by count(*) desc limit 1