What are the carriers of devices that are in stock in more than a single shop?
SELECT T2.Carrier FROM stock AS T1 JOIN device AS T2 ON T1.Device_ID  =  T2.Device_ID GROUP BY T1.Device_ID HAVING COUNT(*)  >  1
SELECT T2.Carrier FROM stock AS T1 JOIN device AS T2 ON T1.Device_ID  =  T2.Device_ID GROUP BY T1.Device_ID HAVING COUNT(*)  >  1
[{'Carrier': 'Bell Mobility'}, {'Carrier': 'Vodafone AU'}]