Database: sales_in_weather
Question: How many stations were able to sell item 5 on January 2014?
SQL: SELECT COUNT(DISTINCT T2.station_nbr) AS number FROM sales_in_weather AS T1 INNER JOIN relation AS T2 ON T1.store_nbr = T2.store_nbr WHERE SUBSTR(`date`, 1, 7) = '2014-01' AND item_nbr = 5