pg.ddx.io  pgsql-sql@postgresql.org mailing list archive  
help / color / mirror / Atom feed
From: George Weaver <gweaver@shaw.ca>
To: lucas@presserv.org
To: pgsql-sql@postgresql.org
Subject: Re: Generic Function
Date: Tue, 15 Mar 2005 05:48:03 -0600
Message-ID: <004b01c52954$dacb5ec0$6400a8c0@Dell4500> (raw)
References: <20050314151555.6kp8nfclzy5cogg0@www.presserv.org>


----- Original Message ----- 
From: <lucas@presserv.org>
To: <pgsql-sql@postgresql.org>
Sent: Monday, March 14, 2005 12:15 PM
Subject: [SQL] Generic Function


> Hi,
> Can I built a generic function like:
> CREATE FUNCTION f (text) RETURNS TEXT as
>  $$
>   return 'select * from $1';
>  $$
> I know its impossible as writed. Also I have looked for EXECUTE procedure 
> but it
> not run the correct function.

If you show us what you've tried and the results you received we may be able 
to help more.

Some points:

     1. To create a string to run with EXECUTE you would need to concatenate 
the above phrase:

         (Assuming "query" has been declared as text): query := 'Select * 
from ' || $1;

    2. Since you're likely returning multiple rows, you need to write your 
function as a set-returning
        function.  See:

    http://www.postgresql.org/docs/8.0/static/plpgsql-control-structures.html#PLPGSQL-RECORDS-ITERATING

      and Executing Dynamic Commands in

    http://www.postgresql.org/docs/8.0/static/plpgsql-statements.html#PLPGSQL-STATEMENTS-PERFORM

> Is there a way to construct this clause? Using plpgsql/pltcl/anything.... 
> ???
>
> Thanks
>
> ---------------------------(end of broadcast)---------------------------
> TIP 5: Have you checked our extensive FAQ?
>
>               http://www.postgresql.org/docs/faq
> 





view thread (4+ messages)  latest in thread

Message-ID: <004b01c52954$dacb5ec0$6400a8c0@Dell4500>
Permalink:  ../004b01c52954$dacb5ec0$6400a8c0@Dell4500/
Also on:    postgresql.org/message-id/004b01c52954$dacb5ec0$6400a8c0@Dell4500

 · 

reply

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: pgsql-sql@postgresql.org
  Cc: gweaver@shaw.ca, lucas@presserv.org
  Subject: Re: Generic Function
  In-Reply-To: <004b01c52954$dacb5ec0$6400a8c0@Dell4500>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox