Postgresql 中的数值数据类型

Question

当我为 postgre sql 编写代码时。我经常得到不需要的数字类型，尤其是 '0.12E3' 十进制形式。

例如，

with data as (
select created_at::timestamp::date as date,count(*)
from posts
group by created_at::timestamp::date
)
select date, count, sum(count) over
(order by date asc rows between unbounded preceding and current row) as total
from data

这段代码以科学计数法的形式给了我累积和的结果。

为什么即使代码中没有浮点数也会发生这种情况？我怎样才能使它正确或避免这种情况发生？

Answer 1

在使用 agragate 时需要使用别名——像这样：

with data as (
  select created_at::timestamp::date as date, count(*) as day_count
  from posts
  group by created_at::timestamp::date
)
select date, day_count, 
       sum(day_count) over (order by date asc rows between unbounded preceding and current row) as total
from data