Question

我想在我的sql项目中同时使用子查询和计算我有一张表A，其中包含以下信息：

表A

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我想找到1月，2月的贡献边际以及1月和2月之间的边际差异。我可以在一个查询中做到这一点以及如何做到这一点？

显示器应具有以下格式：

Month_revenue Income Cost
-------------------------
Jan           100    50
Feb           90     60
Mar           80     40

谢谢！

Answer 1

您只需对表格使用三种选择：

select 
  jan.income - jan.cost as jan,
  feb.income - feb.cost as feb,
  mar.income - mar.cost as mar,
  (jan.income - jan.cost) - (feb.income - feb.cost) as jan_feb,
  (feb.income - feb.cost) - (mar.income - mar.cost) as feb_mar
from
  (select * from mytable where Month_revenue = 'Jan') jan
cross join
  (select * from mytable where Month_revenue = 'Feb') feb
cross join
  (select * from mytable where Month_revenue = 'Mar') mar;

或者你可以有条件地聚合：

select
  sum(case when Month_revenue = 'Jan' then income - cost end) as jan,
  sum(case when Month_revenue = 'Feb' then income - cost end) as feb,
  sum(case when Month_revenue = 'Mar' then income - cost end) as mar,
  sum(case when Month_revenue = 'Jan' then income - cost end) -
  sum(case when Month_revenue = 'Feb' then income - cost end) as jan_feb,
  sum(case when Month_revenue = 'Feb' then income - cost end) -
  sum(case when Month_revenue = 'Mar' then income - cost end) as feb_mar
from mytable;

计算边际收益

1 个答案: