Database: sales_in_weather
Question: Tell the temperature range of the home weather station of store no.7 on 2014/4/28.
SQL: SELECT T1.tmax - T1.tmin AS temprange FROM weather AS T1 INNER JOIN relation AS T2 ON T1.station_nbr = T2.station_nbr WHERE T2.store_nbr = 7 AND T1.`date` = '2014-04-28'