From: Stephan Szabo <sszabo@megazone.bigpanda.com>
To: Don Drake <dondrake@gmail.com>
Cc: pgsql-sql@postgresql.org
Subject: Re: plpgsql functions and NULLs
Date: Mon, 31 Jan 2005 13:31:34 -0800 (PST)
Message-ID: <20050131132701.G12960@megazone.bigpanda.com> (raw)
In-Reply-To: <6c21003b0501301141234c256b@mail.gmail.com>
References: <6c21003b0501301141234c256b@mail.gmail.com>
On Sun, 30 Jan 2005, Don Drake wrote:
> OK, I have a function that finds records that changed in a set of
> tables and attempts to insert them into a data warehouse.
>
> There's a large outer loop of candidate rows and I inspect them to see
> if the values really changed before inserting.
>
> My problem is that when I look to see if the row exists in the
> warehouse already, based on some IDs, it fails when an ID is NULL.
> The ID is nullable, so that's not a problem.
>
> But I'm forced to write an IF statement looking for the potential NULL
> and write 2 queries:
>
> IF omcr_id is null
> select * from ....
> WHERE omcr_id is NULL
> AND ...
> ELSE
> select * from ....
> WHERE omcr_id=candidate.omcr_id
> AND ....
> END IF;
Hmm, perhaps some form like:
WHERE not(candidate.omcr_id is distinct from omcr_id)
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To: pgsql-sql@postgresql.org
Cc: sszabo@megazone.bigpanda.com, dondrake@gmail.com
Subject: Re: plpgsql functions and NULLs
In-Reply-To: <20050131132701.G12960@megazone.bigpanda.com>
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