Question

我正在使用PostgreSQL，其表格架构允许以欧元或美元等不同货币付款。我还有一张表格，其中包含每种货币对美元的转换率。

我想将按月/年分组的每笔转换为美元的付款金额汇总。建议的方法是什么？

我的表是：

CREATE TABLE invoice
(
  invoice_id serial,
  ...
  amount numeric,
  currency_type_id text,
  created_date timestamp without time zone,
);

CREATE TABLE currency_rates
(
  code_from text,
  code_to text,
  rate numeric,
);

我的实际查询只是按月分组的值的总和：

select extract(month from created_date) as mon, 
extract(year from created_date) as yyyy,
sum(amount) as "Sales" 
from invoice 
group by 1,2 
order by 2,1

Answer 1

您应该join到查询表以获取美元以外货币的转换率。

select extract(month from created_date) as mon, 
extract(year from created_date) as yyyy, 
sum(case when c.code_from <> 'USD' then amount * c.rate else amount end) as "Sales" 
from invoice i
join currency_rates c on i.currency_type_id = c.code_from
where c.code_to = 'USD'
group by 1,2 
order by 2,1

多个发票金额的总和转换为货币

1 个答案: