Database: sales_in_weather
Question: Which weather station does the store that sold the highest quantity of item 9 belongs to?
SQL: SELECT station_nbr FROM sales_in_weather AS T1 INNER JOIN relation AS T2 ON T1.store_nbr = T2.store_nbr WHERE T1.item_nbr = 9 GROUP BY T2.station_nbr ORDER BY SUM(T1.units) DESC LIMIT 1