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Re: how does select/project work with extra variables?

From: Seaborne, Andy <andy.seaborne@hp.com>
Date: Tue, 22 Mar 2005 09:09:49 +0000
Message-ID: <423FE0DD.90908@hp.com>
To: Dan Connolly <connolly@w3.org>
CC: RDF Data Access Working Group <public-rdf-dawg@w3.org>

Dan Connolly wrote:
> Bob write:
> 
> --------
> First, I am assuming that the
> following query returns no bindings:
> 
> SELECT ?x ?y
>   WHERE  { ?book dc10:title ?x }
>  
> I shouldn't since it doesn't refer to OPTIONAL or UNION within the query, and the
> spec cites those as prerequisites for allowing unbound values.
> --------
>  --
> http://lists.w3.org/Archives/Public/public-rdf-dawg-comments/2005Mar/0048.html
> 
> but I don't see it that way... my reading of 
>   http://www.w3.org/2001/sw/DataAccess/rq23/#select
> is that SELECT (i.e. projection) doesn't cause solutions
> to get rejected. The ?y is just noise.

Correct.

> 
> 
> Would somebody please add this as a test case? EricP?
> 

3 added (1 var in query, one in select; 1 in query, 2 in select; 2 in query, 1 
in select (carefully avoiding any issues about DISTINCT).

	Andy
Received on Tuesday, 22 March 2005 09:11:14 GMT

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