Date: Tue, 15 Mar 2005 05:48:03 -0600
From: George Weaver <gweaver@shaw.ca>
Subject: Re: Generic Function
To: lucas@presserv.org, pgsql-sql@postgresql.org
Message-id: <004b01c52954$dacb5ec0$6400a8c0@Dell4500>
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----- 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
>
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