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Re: ISSUE-35: DISTINCT/aggregates

From: Steve Harris <steve.harris@garlik.com>
Date: Wed, 3 Feb 2010 15:11:04 +0000
Cc: SPARQL Working Group <public-rdf-dawg@w3.org>
Message-Id: <C8B358BA-E91E-4625-A2AC-4EF0BC783AA7@garlik.com>
To: Andy Seaborne <andy.seaborne@talis.com>
On 3 Feb 2010, at 14:09, Andy Seaborne wrote:
> On 03/02/2010 12:15 PM, Steve Harris wrote:
>> On 3 Feb 2010, at 08:42, Andy Seaborne wrote:
>> ...
>>> ISSUE-35
>>> Can aggregate functions take DISTINCT as an argument a la SELECT
>>> COUNT(DISTINCT ?X)?
>>>
>>> DONE All built-in aggregates can take the word DISTINCT.
>>> Custom ones do not; it's part of their definition,
>>> i.e. different URIs for a DISTINCT and non DISTINCT form.
>>
>> I thought that the custom ones could also take DISTINCT? My  
>> recollection
>> may well be wrong though. Do you have a link to the strawpoll?
>
> By using a keyword argument, it undermines the idea that the URI  
> identifies one thing - it's really now two, the DISTINCT and non- 
> DISTINCT versions.
>
> I'd expect COUNT(*) and COUNT(DISTINCT *) to have different URIs.

Ah, interesting, I wouldn't.

E.g. GROUP_CONCAT(DISTINCT ?x ORDER BY STRLEN(?x)) wouldn't have a  
different URI to GROUP_CONCAT(DISTINCT ?x) either.

In my mind the DISTINCT is part of the expression, not part of the  
function.

- Steve
Received on Wednesday, 3 February 2010 15:11:33 GMT

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