解答
140
SQL文(クエリ)
SELECT CASE WHEN prefecture IN("東京", "千葉", "埼玉", "神奈川") THEN "東京圏" WHEN prefecture IN("大阪", "奈良", "兵庫", "京都") THEN "大阪圏" ELSE NULL END AS area , SUM(revenue) AS sum_rev FROM sample.sales LEFT JOIN sample.customers USING (user_id) GROUP BY area HAVING area IS NOT NULL ORDER BY sum_rev DESC