On Wed, Sep 23, 2009 at 8:13 AM, AnthonyV <avequeau@gmail.com> wrote:
> Hello,
>
> I have a table like :
>
> date | value
> -------------------------------
> 2009-09-19 | 1
> 2009-09-20 | 2
> 2009-09-21 | 6
> 2009-09-22 | 9
> 2009-09-23 | 1
>
> I'd like a request which gives me the sum of each last n days.
> For example, if I want the sum of each 3 days, I want this result:
>
> date | sum_value
> -------------------------------
> 2009-09-19 | 1 (sum from 2009-09-17 to 2009-09-19)
> 2009-09-20 | 3 (sum from 2009-09-18 to 2009-09-20)
> 2009-09-21 | 9 (sum from 2009-09-19 to 2009-09-21)
> 2009-09-22 | 17 (sum from 2009-09-20 to 2009-09-22)
> 2009-09-23 | 16 (sum from 2009-09-21 to 2009-09-23)
>
> I try to make a subquery which is apply on each row of a query, but it
> does work.
select date, (select count(*) from foo where date between f.date - 1
and f.date + 1) from foo f;