CREATE TABLE stock (shop_id NUMBER, device_id NUMBER, quantity NUMBER)
CREATE TABLE device (device_id NUMBER, device CLOB, carrier CLOB, package_version CLOB, applications CLOB, software_platform CLOB)
CREATE TABLE shop (shop_id NUMBER, shop_name CLOB, location CLOB, open_date CLOB, open_year NUMBER)

Show names of shops that have more than one kind of 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
SELECT "T2"."shop_name" FROM "stock" "T1" JOIN "shop" "T2" ON "T1"."shop_id" = "T2"."shop_id" GROUP BY "T1"."shop_id" HAVING COUNT(*) > 1