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Re: Prioritised list of open issues (query, my bits)

From: Steve Harris <steve.harris@garlik.com>
Date: Tue, 9 Feb 2010 09:52:51 +0000
Cc: "public-rdf-dawg@w3.org Group" <public-rdf-dawg@w3.org>
Message-Id: <7F628DB7-37B3-4D86-B858-7062C41F7970@garlik.com>
To: Andy Seaborne <andy.seaborne@talis.com>
On 9 Feb 2010, at 09:00, Andy Seaborne wrote:
> On 08/02/2010 10:23 AM, Steve Harris wrote:
>> http://www.w3.org/2009/sparql/track/issues/35
>> Can aggregate functions take DISTINCT as an argument a la SELECT
>> COUNT(DISTINCT ?X)?
>> - Seems consensus on yes.
>
> A URI should name the function, not a collection of related  
> functionality.
>
> Example:
>
> COUNT(DISTINCT ?x) vs COUNT(?x)
>
> How do you name the difference if they are not different URIs?

In my view, DISTINCT does not change the function, it changes the  
(multi)set that the function is applied to, c.f. http://www.w3.org/2009/sparql/docs/query-1.1/rq25.xml#aggregateAlgebra

More concretely, you form a DISTINCT multiset of the bound values of ? 
x, then apply the count function to the resulting set.

> In custom aggregates, what does my:agg name?

The aggregate function, defined as per the aggregate functions in 9.2.

- Steve

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Received on Tuesday, 9 February 2010 09:53:23 GMT

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