- From: Andy Seaborne <andy@apache.org>
- Date: Sat, 26 Nov 2016 20:07:49 +0000
- To: public-sparql-exists@w3.org
On 26/11/16 18:47, Peter F. Patel-Schneider wrote:
> I have added a new test and shown what I think the results for several
> setups are are on some data. The "Expected" results are what I think should
> be expected from the fixed definition of SPARQL that the group is supposed
> to produce.
>
> Graph
> :s :p :v .
> :t :r :w .
>
>
> SELECT ?x WHERE {
> ?x :p :v .
> FILTER ( EXISTS {
> FILTER ( ?x = :s ) )
> } )
> }
>
> Specification { { (x,:s) } }
> Proposal A { { (x,:s) } }
> Proposal B { }
> Expected { { (x,:s) } }
Proposal B gets { { (x,:s) } }
There is a empty BGP that the FILTER ( ?x = :s ) applies to which is no
removed by simplification so it injects ?x. Filter in the algebra always
filters the results of a pattern.
(prefix ((: <http://example/>))
(project (?x)
(filter (exists
(filter (= ?x :s)
(bgp empty)))
(bgp (triple ?x :p :v)))))
My prototype gets:
------
| x |
======
| :s |
------
Andy
(PS This may become a duplicate - I sent a copy from the wrong address a
few mins ago)
Received on Saturday, 26 November 2016 20:08:24 UTC