Leetcode Note: MySQL - Customer Placing the Largest Number of Orders

Customer Placing the Largest Number of Orders - LeetCode
https://leetcode.com/problems/customer-placing-the-largest-number-of-orders/

• MySQL で取り組んだメモ

所感

• Orders table から最も order_number の頻度が大きいレコードの customer_number を抽出する
• つまり、最も多く注文している customer を特定する

回答

Customer Placing the Largest Number of Orders - LeetCode https://leetcode.com/problems/customer-placing-the-largest-number-of-orders/solution/

SELECT customer_number FROM Orders GROUP BY customer_number ORDER BY COUNT(*) DESC LIMIT 1;

• GROUP BY で customer_number を集計
• ORDER BY COUNT(*) DESC で出現回数を降順で取得
• LIMIT 1 で 1 レコードのみ取得