From: Jasen Betts <jasen@xnet.co.nz>
To: pgsql-sql@postgresql.org
Subject: Re: Setting a default value for a select statement without results
Date: 6 Feb 2013 04:07:37 GMT
Message-ID: <kesku9$ih0$2@gonzo.reversiblemaps.ath.cx> (raw)
References: <CAAY=A7_cM2ZrO9oD=_pbuX6vdNiVST3iXLfRDZ5_YHASoABZBg@mail.gmail.com>
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On 2013-02-06, JORGE MALDONADO <jorgemal1960@gmail.com> wrote:
> --f46d0401fb2fcb805e04d50354b1
> Content-Type: text/plain; charset=ISO-8859-1
>
> I have an UPDATE query with the following general structure:
>
> UPDATE table1 SET (SELECT field FROM table2 WHERE conditions ORDER BY
> order_field LIMIT 1)
assuming you mean this, and you are happy with its performance.
UPDATE table1 SET field1 = (SELECT field FROM table2 WHERE conditions ORDER BY
order_field LIMIT 1)
> Is it possible to assign a default value in case no results are returned by
> the SELECT statement?
use coalesce.
UPDATE table1 SET field1 = coalesce( (SELECT field FROM table2 WHERE conditions ORDER BY
order_field LIMIT 1) , default_value )
--
⚂⚃ 100% natural
--
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To: pgsql-sql@postgresql.org
Cc: jasen@xnet.co.nz
Subject: Re: Setting a default value for a select statement without results
In-Reply-To: <kesku9$ih0$2@gonzo.reversiblemaps.ath.cx>
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