DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma;
	h=message-id:date:from:to:cc:subject:references:mime-version
	:content-type:content-disposition:in-reply-to:user-agent;
	b=rinXEGCNnA/2yDaRPMrJRsu/e1IOXA07YEIsrTRt4VFBcNy2WDZ+7Bp5HVRrCeNtwt
	vVVkD6/07AcY5PfUFs1DnCGtU2exTmjxW0iy/95NNO/pKNBlRaskCOh1TNJJHS6o2ZQU
	v+cEpokYXPb/h3I2vCtv1SCGYaE8+pTCy6VMU=
Message-ID: <4cb3e194.ea05ec0a.3e4b.06b2@mx.google.com>
Date: Mon, 11 Oct 2010 22:18:22 -0600
From: Joshua Tolley <eggyknap@gmail.com>
To: Andreas <maps.on@gmx.net>
Cc: pgsql-sql@postgresql.org
Subject: Re: Is there a conditional string-concatenation ?
References: <4CB3DF63.6080909@gmx.net>
MIME-Version: 1.0
Content-Type: multipart/signed; micalg=pgp-sha1;
	protocol="application/pgp-signature"; boundary="H+4ONPRPur6+Ovig"
Content-Disposition: inline
In-Reply-To: <4CB3DF63.6080909@gmx.net>
User-Agent: Mutt/1.5.18 (2008-05-17)


--H+4ONPRPur6+Ovig
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline

On Tue, Oct 12, 2010 at 06:09:07AM +0200, Andreas wrote:
>  Hi,
> Is there a conditional string-concatenation ?

Perhaps this:

CREATE OR REPLACE FUNCTION mycat(text, text, text) RETURNS TEXT LANGUAGE sql
IMMUTABLE AS $$
SELECT CASE
    WHEN $1 IS NULL OR $1 = '' THEN trim($3)
    WHEN $3 IS NULL OR $3 = '' THEN trim($1)
    ELSE trim($1) || trim(coalesce($2, '')) || trim($3)
END;

--
Joshua Tolley / eggyknap
End Point Corporation
http://www.endpoint.com

--H+4ONPRPur6+Ovig
Content-Type: application/pgp-signature; name="signature.asc"
Content-Description: Digital signature
Content-Disposition: inline

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.9 (GNU/Linux)

iEYEARECAAYFAkyz4Y4ACgkQRiRfCGf1UMMfDQCff8A3r4rXAwvO//RV5XM/Jd2d
VuEAnAkHuI9DAoyesUchv6195SVZKZ7l
=HOzF
-----END PGP SIGNATURE-----

--H+4ONPRPur6+Ovig--