Re: graphing time series data
От | Pavel Stehule |
---|---|
Тема | Re: graphing time series data |
Дата | |
Msg-id | y2l162867791004140914r15b6fdbzd8da3d2ff279e455@mail.gmail.com обсуждение исходный текст |
Ответ на | Re: graphing time series data (Louis-David Mitterrand <vindex+lists-pgsql-sql@apartia.org>) |
Список | pgsql-sql |
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 > > > -- > Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-sql >
В списке pgsql-sql по дате отправления: