解答
141
SQL文(クエリ)
WITH master AS ( SELECT user_id , SUM(revenue) AS sum_rev FROM sample.sales GROUP BY user_id ) SELECT DATE_DIFF("2019-12-31", birthday, YEAR) AS age , SUM(sum_rev) AS sum_rev FROM master LEFT JOIN sample.customers USING (user_id) GROUP BY age HAVING age IS NOT NULL ORDER BY sum_rev DESC LIMIT 3