What is the ID of the item that sold the best on the day with the highest max temperature in store no.3 in 2012?
highest max temperature refers to Max(tmax); store no.3 refers to store_nbr = 3; in 2012 refers to substring (date, 1, 4) = '2012'; sold the best refers to Max(units); ID of the item refers to item_nbr
SELECT T1.item_nbr FROM sales_in_weather AS T1 INNER JOIN relation AS T2 ON T1.store_nbr = T2.store_nbr INNER JOIN weather AS T3 ON T2.station_nbr = T3.station_nbr WHERE T1.store_nbr = 3 AND T1.`date` LIKE '%2012%' AND tmax = ( SELECT MAX(tmax) FROM sales_in_weather AS T1 INNER JOIN relation AS T2 ON T1.store_nbr = T2.store_nbr INNER JOIN weather AS T3 ON T2.station_nbr = T3.station_nbr WHERE T1.store_nbr = 3 AND T1.`date` LIKE '%2012%' ) GROUP BY T1.item_nbr ORDER BY SUM(units) DESC LIMIT 1