利用Sakila数据库练习SQL查询

1. 查询所有电影的数量

SELECT COUNT(*) AS total_movies FROM film; 

2. 查询所有电影的平均租金

SELECT AVG(rental_rate) AS avg_rental_rate FROM film; 

3. 查询电影库存大于10的电影名称和库存量

SELECT title, inventory_id FROM film WHERE inventory_id > 10; 

4. 查询租借记录中每个客户借阅电影的总数量

SELECT customer_id, COUNT(*) AS total_rentals FROM rental GROUP BY customer_id; 

5. 查询最近一个月内租借次数最多的电影

SELECT film_id, COUNT(*) AS total_rentals FROM rental WHERE rental_date >= DATE_SUB(NOW(), INTERVAL 1 MONTH) GROUP BY film_id ORDER BY total_rentals DESC LIMIT 1;