- From: Andy Seaborne <andy.seaborne@epimorphics.com>
- Date: Sun, 30 Jan 2011 19:02:34 +0000
- To: "SPARQL Working Group \">" <"\"\"public-rdf-dawg\""@w3.org>
http://www.w3.org/2009/sparql/wiki/CommentResponse:JP-3 Drafted - ready for review > (I've sent a version of this to Jorge offlist as discussions aren't possible on the comments list). So he's seen the gist of the reply, Andy On 26/01/11 14:39, Andy Seaborne wrote: > > > On 26/01/11 13:53, Matthew Perry wrote: >> I think this should work for the sum age query. >> >> SELECT SUM(?A) >> WHERE >> { ?F :age ?A >> { SELECT DISTINCT ?F >> WHERE >> { :me (:friend)+ ?F } }} >> >> It seems that, in general, DISTINCT will work as a there exists query >> when URIs and blank nodes are the endpoint of a path because we have a >> one-to-one mapping between URI/BN values and graph vertices, but we get >> a one-to-many mapping from literal values to vertices. > > Yes, that example addresses Jorge's use case and contrasts nicely with > the basket example where there is a need for duplicate matches from the > property path itself (although, in the syntax triple patterns are > property paths of length 1). > > Andy
Received on Sunday, 30 January 2011 19:03:11 UTC