Database: sales_in_weather
Question: How many units of item no.9 were sold in store no.1 in total in January, 2012?
SQL: SELECT SUM(units) FROM sales_in_weather WHERE SUBSTR(`date`, 6, 2) = '01' AND SUBSTR(`date`, 1, 4) = '2012' AND item_nbr = 9 AND store_nbr = 1