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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 ?
Date: Mon, 11 Oct 2010 22:18:22 -0600
Message-ID: <4cb3e194.ea05ec0a.3e4b.06b2@mx.google.com> (raw)
In-Reply-To: <4CB3DF63.6080909@gmx.net>
References: <4CB3DF63.6080909@gmx.net>

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

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