PostgreSQL - 哪个电影类别在我们的客户中最受欢迎？

Question

我想回答一个具体问题“哪个电影类别在我们的客户中最受欢迎？”我有这个查询来修改：

SELECT  f.title, COUNT(*) AS RentalCount
  FROM  film f
    INNER JOIN film_category fc ON fc.film_id = f.film_id
    INNER JOIN category c ON c.category_id = fc.category_id
    INNER JOIN inventory i ON i.film_id = f.film_id
    INNER JOIN rental r ON r.inventory_id = i.inventory_id
  WHERE (c.name = 'Sports')
  GROUP BY f.title
  ORDER BY 2 DESC;

This is the ER Diagram

谢谢！

Answer 1

你非常接近你的查询。基本上，您只需按类别汇总：

SELECT c.name, COUNT(*) AS RentalCount
FROM film_category fc JOIN
     category c
     ON c.category_id = fc.category_id JOIN
     inventory i
     ON i.film_id = fc.film_id JOIN
     rental r
     ON r.inventory_id = i.inventory_id
GROUP BY c.name
ORDER BY RentalCount DESC
LIMIT 1;