Re: Allow an alias to be attached directly to a JOIN ... USING - Mailing list pgsql-hackers

From Peter Eisentraut
Subject Re: Allow an alias to be attached directly to a JOIN ... USING
Date
Msg-id 91c3880a-de95-324d-1d75-3ed512b221b6@2ndquadrant.com
Whole thread Raw
In response to Re: Allow an alias to be attached directly to a JOIN ... USING  (Wolfgang Walther <walther@technowledgy.de>)
List pgsql-hackers
On 2020-08-03 19:44, Wolfgang Walther wrote:
> So given this:
> 
> SELECT x.id FROM a LEFT JOIN b USING (id) AS x
> 
> will this return NULL or a.id for rows that don't match in b? This
> should definitely be mentioned in the docs and I guess a test wouldn't
> be too bad as well?

This issue is independent of the presence of the alias "x", so I don't 
think it has to do with this patch.

There is a fair amount of documentation on outer joins, so I expect that 
this is discussed there.

-- 
Peter Eisentraut
2ndQuadrant, an EDB company
https://www.2ndquadrant.com/



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