From: Alvaro Herrera <alvherre@commandprompt.com>
To: Neil Harkins <nharkins@well.com>
Cc: pgsql-sql@postgresql.org
Subject: Re: concatenation with a null column (using ||) nulls the result?
Date: Mon, 10 Apr 2006 17:55:56 -0400
Message-ID: <20060410215556.GB5856@surnet.cl> (raw)
In-Reply-To: <Pine.SOL.4.10.10604101430250.2779-100000@well.com>
References: <Pine.SOL.4.10.10604101430250.2779-100000@well.com>
Neil Harkins wrote:
> Note: The cabinets_description for the "548-4th-Cab1" row is " ",
> not NULL, hence it being displayed. Is this standard SQL behavior?
Yes; something || NULL yields NULL. If you want NULL to behave as ""
for the purpose of the concatenation, try
SELECT cabinets_name || ' - ' || COALESCE(cabinets_description, '') AS concat
FROM cabinets WHERE cabinets_datacenters = 2;
I'm assuming cabinets_name is NOT NULL, so it doesn't need COALESCE.
--
Alvaro Herrera http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support
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To: pgsql-sql@postgresql.org
Cc: alvherre@commandprompt.com, nharkins@well.com
Subject: Re: concatenation with a null column (using ||) nulls the result?
In-Reply-To: <20060410215556.GB5856@surnet.cl>
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