- From: Steve Harris <steve.harris@garlik.com>
- Date: Mon, 27 Sep 2010 13:20:54 +0100
- To: Andy Seaborne <andy.seaborne@epimorphics.com>
- Cc: Axel Polleres <axel.polleres@deri.org>, SPARQL Working Group <public-rdf-dawg@w3.org>
On 2010-09-23, at 08:36, Andy Seaborne wrote:
>
>
> On 22/09/10 06:59, Axel Polleres wrote:
>> I have a small question about the Definition of "Group" in the query draft:
>>
>> "Group((),Ω) = { 1 -> Ω }"
>>
>> ... shouldn't that be:
>>
>> "Group((),Ω) = { () -> Ω }"
>>
>> i.e., what is the 1 supposed to mean?
>
> The 1 is any key. When the set of groups keys is the empty, which happnes for
>
> SELECT (count(*) AS ?c) { ?s ?p ?o }
>
> then there needs to be a key value for the group.
>
> It could be said to be slightly more sense to be (1), not 1, as it's a list when then the key isn't empty. The key just needs to be unique, and here, there is only one key so it's arbitrary.
Yeah, I went for a non-list value so there was no possibility of it being the same as a "real" key, but it's perhaps not as clear as it should be.
- Steve
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Received on Monday, 27 September 2010 12:21:29 UTC