1341. 电影评分

请你编写一组 SQL 查询：

查找评论电影数量最多的用户名。
如果出现平局，返回字典序较小的用户名。

查找在 2020 年 2 月 平均评分最高 的电影名称。
如果出现平局，返回字典序较小的电影名称。

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题意就是查找两个结果，然后都用result显示即可，那么我们想到用UNION。

第一部分 查找评论电影数量最多的用户名

SELECT u.name AS results
FROM Movie_Rating AS m
INNER JOIN Users AS u 
ON u.user_id = m.user_id
GROUP BY m.user_id 
ORDER BY COUNT(m.user_id) DESC, u.name
LIMIT 1

即联结用户和评分表，找出评论数量最多的name即可

SELECT title AS results 
FROM Movies 
INNER JOIN
(
    SELECT m.movie_id 
    FROM Movie_Rating AS m
    INNER JOIN Movies AS m_1 
    ON m_1.movie_id = m.movie_id
    WHERE created_at BETWEEN '2020-02-01' AND '2020-02-29'
    GROUP BY m.movie_id
    ORDER BY AVG(rating) DESC, title
    LIMIT 1
) AS temp_1
ON temp_1.movie_id = Movies.movie_id

找到电影平均评分最高的电影名称

SELECT m_1.title AS results 
    FROM Movie_Rating AS m
    INNER JOIN Movies AS m_1 
    ON m_1.movie_id = m.movie_id
    WHERE created_at BETWEEN '2020-02-01' AND '2020-02-29'
    GROUP BY m.movie_id
    ORDER BY AVG(rating) DESC, title
    LIMIT 1