如何在postgresql中计算group by中的百分比？

我有一个对公司名称、规模和收入进行分组的查询。这是我的疑问：

with Test as
(select
id.name as Company
,CASE WHEN li.segment = 'Large' then 'Large Cap'
      WHEN li.segment = 'Medium' then 'Mid Cap'
      WHEN li.segment = 'Small' then 'Small Cap' else NULL end as Size
,sum(ia.amount) as Revenue
from base.company_rev ia
join base.company_detail id on id.company_account_id = ia.company_account_id
left join base.product_issued li on li.product_id = ia.product_id
where 1 = 1
and ia.create_date::date between '2018-05-01' and '2018-05-31'
group by id.name, li.segment
order by 1, 2, 3)

 select * 
 from Test
 group by company, size, revenue
 order by 1, 2, 3

我如何增加每家公司规模所占收入的百分比？我想根据尺码分组中的美元金额来做

前

---

（ia.amount/sum（ia.amount））*100（百分比）

您正在寻找一个窗口函数，即

sum（）OVER（）

---

为什么要对公司进行两次聚合？

orderby

在子查询中（在您的

WITH

子句中）是多余的。主查询中的

分组依据

也是多余的，因为它包含所有列，因此什么也不做。最后：使用positional

ORDER BY

被认为是不好的风格。改用名字，这太完美了。谢谢

Company A...Large Cap...15m = 60% (15/25)
Company A...Mid Cap...10m = 40% (10/25)

with test as
(
  select
    id.name as company
    ,case when li.segment = 'Large' then 'Large Cap'
          when li.segment = 'Medium' then 'Mid Cap'
          when li.segment = 'Small' then 'Small Cap' 
          else null end as size
    ,sum(ia.amount) as revenue
  from base.company_rev ia
  join base.company_detail id on id.company_account_id = ia.company_account_id
  left join base.product_issued li on li.product_id = ia.product_id
  where 1 = 1
  and ia.create_date::date between date '2018-05-01' and date '2018-05-31'
  group by id.name, li.segment
)
select
  company, 
  size, 
  revenue,
  revenue / sum(revenue) over (partition by company) * 100 as percentage
from test
order by company, size, revenue;