Message-Id: <491AB2F3-6ACF-4D58-A195-9D7A848E479A@myemma.com>
From: Erik Jones <erik@myemma.com>
To: "pgsql-sql@postgresql.org List" <pgsql-sql@postgresql.org>
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Subject: Testing for null record in plpgsql
Date: Thu, 10 Apr 2008 23:16:40 -0500

Ok, let's say I have the following:

CREATE TABLE foo (
	val1 integer,
	val2 integer
);

CREATE OR REPLACE FUNCTION returns_null_maybe()
	RETURNS foo AS $$
DECLARE
	res integer;
BEGIN
	SELECT INTO res extract('month' from now()::integer % 2;
=09
	IF res =3D=3D 0 THEN
		RETURN NULL;
	ELSE
		RETURN (5,5)::foo;
	END IF;
END;
$$ LANGUAGE plpgsql;

Now, let's say I want to call this from another function and test the =20=

result to see if I have a null record (null, null),.  I've got the =20
following working but it feels like there should be something much =20
simpler but I just can't seem to hit on it.  Is this it?

CREATE FUNCTION test_null_rec()
	RETURNS boolean AS $$
DECLARE
	res boolean;
	null_rec foo;
BEGIN
	SELECT INTO res * FROM returns_null_maybe();

	IF row(res.*) IS DISTINCT FROM row(null_rec.*) THEN
		RETURN TRUE;
	ELSE
		RETURN FALSE;
	END IF;
END;
$$ LANGUAGE plpgsql;

Erik Jones

DBA | Emma=AE
erik@myemma.com
800.595.4401 or 615.292.5888
615.292.0777 (fax)

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