Re: Group By? - Mailing list pgsql-general

On Mon, Nov 21, 2005 at 21:53:10 -0800,
  Bob Pawley <rjpawley@shaw.ca> wrote:
> Here's what I want to do.
>
> Table control contains values (mon and valves) that are associated by
> numbers inserted into the associated column.
>
> I want to transfer the serial _id number of the items associated by the
> value '1' into the appropriate columns of the first row of the table
> auto_control. All items associated with the value '2' into the second row -
> etc. etc.

You don't really want to do that. Tables have fixed numbers of columns and
what you want to do doesn't result in a fixed number of columns.

If you want to generate a report with that format, then I think there is
a contrib module (crosstabs?) that will do this kind of thing. You could
also have a report app do it for you. In the report app method, you would
be best to return rows ordered by association and then device_ID and have the
app check for when the association value changes.

>
> Is this best accomplished by a 'group by' command or subset???
>
> Bob
>      Control
>
>      device_ID type association
>      serial varchar int4
>
>      1 mon 1
>      2 valve 2
>      3 valve 1
>      4 mon 2
>      5 valve 1
>
>
>      Auto_control
>
>      loop_id mon valve valve
>      serial int4 int4 int4
>      1 1 3 5
>      2 2 4
>
>
>
> ----- Original Message -----
> From: "Guy Rouillier" <guyr@masergy.com>
> To: "Postgre General" <pgsql-general@postgresql.org>
> Sent: Monday, November 21, 2005 4:25 PM
> Subject: Re: [GENERAL] Group By?
>
>
> Converted your message to plain text as preferred on most mailing lists.
>
> Bob Pawley wrote:
> >I want to take the serial ID of several values in different rows in
> >one table and insert them into a single row of another table.
> >
> >Would the 'group by' command be the best way to do this?
>
> Could you provide an actual example?  The wording of your question is a
> little vague and an example might help solicit an answer to the actual
> problem.  For example, are these serial ID values all in a the same
> column in the source table?  Or is each one in a different column?  And
> what is the selection criteria that brings these results together?
>
> --
> Guy Rouillier
>
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