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Re: example query on aggregates in SPARQL/Query Section 2

From: Axel Polleres <axel.polleres@deri.org>
Date: Thu, 5 Nov 2009 10:31:28 -0800
Cc: SPARQL Working Group <public-rdf-dawg@w3.org>
Message-Id: <A51FE31B-49F3-4C8B-94AC-CC51D96CB925@deri.org>
To: Axel Polleres <axel.polleres@deri.org>
Sorry guys, I mainly got confused with the example.
There's nothing wrong with the issue, but I still think that the  
example query is laying a trap,
as users might assume that this also works if there are several  
authors from the same org for the same book.

Axel

On 5 Nov 2009, at 09:58, Axel Polleres wrote:

> Just browsing over the example again and rethinking our discussion  
> regarding implicit grouping...
>
> PREFIX  <http://books.example/>
> SELECT SUM(?lprice) AS ?totalPrice
> WHERE {
>  ?org :affiliates ?auth .
>  ?auth :writesBook ?book .
>  ?book :price ?lprice
> }
> GROUP BY ?org
> HAVING (SUM(?lprice) > 10)
>
>
> has ungrouped variables book, auth...Looking at our resolution, I  
> honestly don't get my head around the semantics here:
>
> "Consensus on prohibiting projecting variables/functions on  
> variables that are not included in the group by clause. Details are  
> pending discussion of ISSUE-41."
>
> That doesn't seem to cover this case, where there are ungrouped  
> variables that *don't* appear in projections or scalar functions.
> Obviously, that query doesn't becomes weird if there are more than  
> one authors from the same org, or if there are several prices for  
> the same book.
>
> Opinions to resolve?
>
> best,
> Axel
>
Received on Thursday, 5 November 2009 18:32:07 GMT

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