Among the days on which over 100 units of item no.5 were sold in store no.3, on which date was the temperature range the biggest?
over 100 units refers to units > 100; item no. 5 refers to item_nbr = 5; store no.3 refers to store_nbr = 3; the temperature range was the biggest refers to Max(Subtract(tmax, tmin))
SELECT T2.`date` FROM relation AS T1 INNER JOIN sales_in_weather AS T2 ON T1.store_nbr = T2.store_nbr INNER JOIN weather AS T3 ON T1.station_nbr = T3.station_nbr WHERE T2.store_nbr = 3 AND T2.item_nbr = 5 AND T2.units > 100 ORDER BY tmax - tmin DESC LIMIT 1