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Re: Help with function

From: Stephan Szabo <sszabo(at)megazone(dot)bigpanda(dot)com>
To: CHRIS HOOVER <CHRIS(dot)HOOVER(at)companiongroup(dot)com>
Cc: pgsql-sql(at)postgresql(dot)org
Subject: Re: Help with function
Date: 2004-09-21 15:25:44
Message-ID: 20040921082228.O11758@megazone.bigpanda.com (view raw or flat)
Thread:
Lists: pgsql-sql
On Tue, 21 Sep 2004, CHRIS HOOVER wrote:

> Thanks a bunch for the pointers and help.
>
> One other hopefully quick question.
>
> How do you query using a variable containing the query?
>
> I'm trying to build a select statment based upon what parameters are being
> passed to the function.
>
> somthing like this:
>
> Declare
> Param1 varchar;
> Param2 varchar;
> SQLStr varchar;
> Table_rec Table%ROWTYPE;
> Begin
>
> SQLStr:="select * from table"
>  Param1:= $1;
> Param2 :=$2;
>
> if (Param1 is not null) then
>   SQLStr := SQLStr || "where column=Param1";
> else
>   SQLStr := SQLStr || "where column=Param2";
> end if;
> SQLStr := SQLStr || ";"
>
> for Table_Rec in SQLStr loop
>   return next Table_rec;
> end loop;
> return;
>
> end;
>
> Is this possible?

Pretty much yes.  You can use the
FOR <record> IN EXECUTE <sqlstring> LOOP
structure to run the query.  The only thing is that
you have to put the values into the string not the name
of the parameters (probably using quote_literal).

So rather than
SQLStr := SQLStr || "where column = Param1";
you'd want something like:
SQLStr := SQLStr || "where column = " || quote_literal(Param1);

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Next:From: Marco GaiarinDate: 2004-09-21 15:42:09
Subject: Porting problem from Informix to Postgres...
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