SELECT rental_date, return_date, customer_id FROM rental WHERE customer_id = 5; ◼顧客ごとのレンタル件数を集計する SELECT customer.customer_id, customer.first_name, customer.last_name, count(*) as レンタル件数 FROM customer LEFT OUTER JOIN rental ON customer.customer_id = rental.customer_id GROUP BY customer.customer_id, customer.first_name, customer.last_name; 20 Copyright© 2018 GxP, Inc.