2010/4/14 Louis-David Mitterrand <vindex+lists-pgsql-sql@apartia.org>:
> On Wed, Apr 14, 2010 at 06:06:59PM +0200, Pavel Stehule wrote:
>> I don't understand well. Why you don't use a function date_trunc(),
>>
>> select date_trunc('week', created), count(*)
>> from price
>> group by date_trunc('week', created)
>
> Because if a price doesn't change for more than a week, then some weeks
> will have bad statistical distribution (i.e not including prices which
> only have their 'modified' updated). So I (think I) need to (1) generate
> the weeks separately and (2) average prices that are current for each
> week.
>
> But I could be missing something obvious.
ok
Pavel
>
>
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