-- 先对表进行Month,Region分组求和，然后再 Region分组求平均
select Month,Region,sum(Revenue) as Revenue,t2.Average from 你的表 as t1 group by Month,Region
left join (select Region,avg(Revenue) as Average from 你的表 group by Region) as t2
on t1.Region=t2.Region

-- 先对表进行Month,Region分组求和，然后再 Region分组求平均，如果报错误，就下面
select t1.Month,t1.Region,sum(Revenue) as Revenue,t2.Average from 你的表 as t1 group by Month,Region
left join (select Region,avg(Revenue) as Average from 你的表 group by Region) as t2
on t1.Region=t2.Region

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