Re: Help with function - Mailing list pgsql-sql

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?

Thanks again for any help,

Chris
------------------( Forwarded letter 1 follows )---------------------
Date: Mon, 20 Sep 2004 13:51:09 -0700 (PDT)
To: chris.hoover
Cc: pgsql-sql@postgresql.org.comp
From: Stephan.Szabo[sszabo]@megazone.bigpanda.com.comp
Subject: Re: [SQL] Help with function

On Mon, 20 Sep 2004, CHRIS HOOVER wrote:

> I need some help writing a simple function.
>
> Due to some program limitations for a program I run the db's for, I'm having
> to write some simple functions to run some selects.  However, I am not sure
> how to have them correctly return the record(s) selected and/or how to
> properly call them from sql.
>
> Would someone be so kind as to help me with this.
>
> Here is an example function:
>
> CREATE OR REPLACE FUNCTION "public"."test_func" (varchar) RETURNS SETOF
> "public"."test_tbl" AS'
> Declare
>   PCN varchar;
>   test_tbl_rec clmhdr%ROWTYPE;
>
> Begin
>
>   PCN := $1;
>
>   select into test_tbl_rec * from test_tbl where test_tbl.pcn = PCN;
>   return test_tbl_rec;
>
> end;
> 'LANGUAGE 'plpgsql' VOLATILE RETURNS NULL ON NULL INPUT SECURITY INVOKER;

If you want to return sets of rows, you're going to need to loop over the
returned rows from the select using return next.

These links may help:
http://www.varlena.com/varlena/GeneralBits/26.html
http://techdocs.postgresql.org/guides/SetReturningFunctions


> I was trying to call this function from psql using:
> select test_func('asdf');

As a side note, plpgsql set returning functions cannot be called in a
select list, only in the from clause (the above links will have examples).