自学SQL

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自学SQL

【变态难】找出每部电影和单部电影销售冠军之间的销售差，列出电影名，销售额差额

思路：这道题乍一看还挺唬人的，理清思路也挺快。我的想法就是先查询最高销量单部电影想减即可。

select (sum_sale - (b.Domestic_sales + b.International_sales)) as sale_diff,m.Title from (// 子查询主要求筛选单部电影以及求销售总和select count(1) as c,sum(Domestic_sales + International_sales) sum_salefrom Movies,Boxoffice where Movies.id = Boxoffice.Movie_idgroup by Director having c = 1 order by sum_sale desc limit 1  
) t,Movies m,Boxoffice b
where m.id = b.Movie_id