我需要编写一个SQL查询来计算欧洲和亚洲之间的收入差异。我受到app dev的约束,无法分两步计算(分别计算每个大陆的总数,然后计算差异)
这是db:
Sales(s_key, s_key, s_product, s_date, s_amount, s_quantity)
Customer(c_key, c_name, c_city, c_country, c_continent)
您能否帮助我扩展这个计算欧洲收入以增加亚洲收入的查询? 谢谢!
Select Sum(s_amount)
From Sales
Where c_continent = 'Europe'
Group By c_continent
答案 0 :(得分:4)
select sum(case s_continent
when 'Europe' then s_amount
when 'Asia' then -s_amount
end) as EuropeMinusAsia
from Sales