-- Determine the 10 countries with the most purchases; list the names of these countries, as well as the number of purchases; sort the results in decreasing order of purchases.

SELECT name, cnt
FROM (
	SELECT country, sum(qty) as cnt
	FROM (
		SELECT province, sum(qty) as qty
		FROM Purchases
		GROUP BY province
	)
	JOIN province ON province = province.ROWID
	GROUP BY country
	ORDER BY cnt DESC
	LIMIT 10
)
JOIN COUNTRY on country == code
;