Re: HELP with a Query

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От Martijn van Oosterhout
Тема Re: HELP with a Query
Дата
Msg-id 20040221085559.GE28711@svana.org
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Ответ на HELP with a Query  (Alex <alex@meerkatsoft.com>)
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On Sat, Feb 21, 2004 at 05:20:51PM +0900, Alex wrote:
> Hi,
> I need some help with a query.
> I use a reference table to lookup some codes. Everything works well if the
> reference table contains a reference but the query fails if no reference
> fails (Z.ref_code=123456). What I need to is either return 0 or null into
> Z.prim_exch if no reference can be found. Whats the best way to do that ? I
> tried a sub query but also did not succeed.

Lookup an SQL site about OUTER JOINS. Should do what you want.

--
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> If the Catholic church can survive the printing press, science fiction
> will certainly weather the advent of bookwarez.
>    http://craphound.com/ebooksneitherenorbooks.txt - Cory Doctorow

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