前述

知识点回顾：union all和union的区别

• Union：对两个结果集进行并集操作，不包括重复行，同时进行默认规则的排序；
• Union All：对两个结果集进行并集操作，包括重复行，不进行排序；

题目描述

leetcode 题目：1341. 电影评分

Code

(
    select name as results
    from MovieRating MR 
    left join Users U
    on MR.user_id = U.user_id
    group by MR.user_id
    order by count(*) desc, name asc
    limit 1
)
union all
(
    select title 
    from MovieRating MRR
    left join Movies M 
    on MRR.movie_id = M.movie_id
    where created_at between '2020-02-01' and '2020-02-29'
    group by MRR.movie_id
    order by avg(rating) desc, title asc
    limit 1
)