Re: no self-joins in views?

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От Martijn van Oosterhout
Тема Re: no self-joins in views?
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Msg-id 20050210165419.GC19117@svana.org
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Ответ на no self-joins in views?  (Christoph Pingel <ch.pingel@web.de>)
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On Thu, Feb 10, 2005 at 05:13:51PM +0100, Christoph Pingel wrote:
> Hello,
>
> is there any restriction re the use of self joins in views? I have a
> moderately complicated query where I scan the same table twice using
> aliases, and I would like to put that into a view to keep my python
> code clean. However, I get an error 'column xy duplicated'. Is this
> so by design?

It's probably complaining that the *resultset* has two columns with the
same name. Consider:

CREATE VIEW test AS
  SELECT * FROM table, table
  WHERE table.a = table.b;

Basically, the output of the view will have all the columnnames listed
twice. You'll need to rename them to make it work...

Hope this helps,
--
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> Patent. n. Genius is 5% inspiration and 95% perspiration. A patent is a
> tool for doing 5% of the work and then sitting around waiting for someone
> else to do the other 95% so you can sue them.

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