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Re: Draft response to BT-1

From: Steve Harris <steve.harris@garlik.com>
Date: Fri, 7 Oct 2011 16:20:12 +0100
Cc: public-rdf-dawg@w3.org
Message-Id: <0F5CFF5A-9E14-4955-AEF0-3B969C271086@garlik.com>
To: Andy Seaborne <andy.seaborne@epimorphics.com>
Ah, thanks, I see what he is getting at now, draft updated at http://www.w3.org/2009/sparql/wiki/CommentResponse:BT-1

- Steve

On 2011-10-07, at 15:26, Andy Seaborne wrote:

> 
> 
> On 07/10/11 13:15, Steve Harris wrote:
>> Comment:
>> http://lists.w3.org/Archives/Public/public-rdf-dawg-comments/2011Aug/0000.html
>> 
>> Draft response:
>> http://www.w3.org/2009/sparql/wiki/CommentResponse:BT-1
>> 
>> - Steve
>> 
> 
> The example is a bit more complicated because it involved aggregation and select expressions.
> 
> An error in an aggregate is not trapped specifically by the aggregate - it's an error.  In the example it's because the select expression that you get an unbound.
> 
> SELECT ( 1/0 AS ?x ) {}
> 
> is:
> 
> -----
> | x |
> =====
> |   |
> -----
> 
> this then explains the second point: ?c can be bound if AVG is an error because the AVG error is handled in SELECT expressions.
> 
> SELECT
>   ( COALESCE(SUM(?a),"error") AS ?x )
>   (SUM(?a) AS ?y )
> { BIND ("abc" AS ?a) }
> 
> ==>
> 
> ---------------
> | x       | y |
> ===============
> | "error" |   |
> ---------------
> 
> and then HAVING( aggregate error ) is just like a FILTER and error.
> 
> 	Andy
> 

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Received on Friday, 7 October 2011 15:20:46 GMT

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