Re: Re: [SQL] need some magic with generate_series()

From: Andreas <maps(dot)on(at)gmx(dot)net>
To: Alexander Gataric <gataric(at)usa(dot)net>
Cc: Filip Rembiałkowski <plk(dot)zuber(at)gmail(dot)com>, pgsql-sql(at)postgresql(dot)org
Subject: Re: Re: [SQL] need some magic with generate_series()
Date: 2013-01-23 12:11:55
Message-ID: 50FFD38B.50301@gmx.net
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I'm sorry to prove that daft. :(

generate_series needs the startdate of every project to generate the
specific list of monthnumbers for every project.
To join against this the list needs to have a column with the project_id.

So I get something like this but still I cant reference the columns of
the projects within the query that generates the series.

with projectstart ( project_id, startdate )
as
(
select project_id, startdate
from projects
)

select project_id, m
from projectstart as p
left join (
select p.project_id, to_char ( m, 'YYYYMM' )::integer
from generate_series ( p.startdate,
current_date, '1 month'::interval ) as m
) as x
using ( project_id );

Am 23.01.2013 01:08, schrieb Alexander Gataric:
> I would create a common table expression with the series from Filip
> and left join to the table you need to report on.
>
> Sent from my smartphone
>
> ----- Reply message -----
> From: "Andreas" <maps(dot)on(at)gmx(dot)net>
> To: "Filip Rembiałkowski" <plk(dot)zuber(at)gmail(dot)com>
> Cc: "jan zimmek" <jan(dot)zimmek(at)web(dot)de>, <pgsql-sql(at)postgresql(dot)org>
> Subject: [SQL] need some magic with generate_series()
> Date: Tue, Jan 22, 2013 4:49 pm
>
>
> Thanks Filip,
> with your help I came a step further. :)
>
> Could I do the folowing without using a function?
>
>
> CREATE OR REPLACE FUNCTION month_series ( date )
> RETURNS table ( monthnr integer )
> AS
> $BODY$
>
> select to_char ( m, 'YYYYMM' )::integer
> from generate_series ( $1, current_date, '1 month'::interval )
> as m
>
> $BODY$ LANGUAGE sql STABLE;
>
>
> select project_id, month_series ( createdate )
> from projects
> order by 1, 2;
>
>
>
> Am 22.01.2013 22:52, schrieb Filip Rembiałkowski:
> > or even
> >
> > select m from generate_series( '20121101'::date, '20130101'::date, '1
> > month'::interval) m;
> >
> >
> >
> > On Tue, Jan 22, 2013 at 3:49 PM, jan zimmek <jan(dot)zimmek(at)web(dot)de> wrote:
> >> hi andreas,
> >>
> >> this might give you an idea how to generate series of dates (or
> other datatypes):
> >>
> >> select g, (current_date + (g||' month')::interval)::date from
> generate_series(1,12) g;
> >>
> >> regards
> >> jan
> >>
> >> Am 22.01.2013 um 22:41 schrieb Andreas <maps(dot)on(at)gmx(dot)net>:
> >>
> >>> Hi
> >>> I need a series of month numbers like 201212, 201301 YYYYMM to
> join other sources against it.
> >>>
> >>> I've got a table that describes projects:
> >>> projects ( id INT, project TEXT, startdate DATE )
> >>>
> >>> and some others that log events
> >>> events( project_id INT, createdate DATE, ...)
> >>>
> >>> to show some statistics I have to count events and present it as a
> view with the project name and the month as YYYYMM starting with
> startdate of the projects.
> >>>
> >>> My problem is that there probaply arent any events in a month but
> I still need this line in the output.
> >>> So somehow I need to have a select that generates:
> >>>
> >>> project 7,201211
> >>> project 7,201212
> >>> project 7,201301
> >>>
> >>> It'd be utterly cool to get this for every project in the projects
> table with one select.
> >>>
> >>> Is there hope?
> >>>
> >>>
> >>> --
> >>> Sent via pgsql-sql mailing list (pgsql-sql(at)postgresql(dot)org)
> >>> To make changes to your subscription:
> >>> http://www.postgresql.org/mailpref/pgsql-sql
> >>
> >>
> >> --
> >> Sent via pgsql-sql mailing list (pgsql-sql(at)postgresql(dot)org)
> >> To make changes to your subscription:
> >> http://www.postgresql.org/mailpref/pgsql-sql
>
>
>
> --
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