- From: Andy Seaborne <andy.seaborne@talis.com>
- Date: Tue, 18 May 2010 14:42:51 +0100
- To: Olivier Corby <Olivier.Corby@sophia.inria.fr>
- CC: SPARQL Working Group <public-rdf-dawg@w3.org>
Mechanical answer: I calculated it as: ==== D.ttl @prefix i: <http://example/> . @prefix n: <http://example/ns#> . i:Jules n:memberOf i:abc . i:Jules n:related i:Jim . i:Jim n:memberOf i:def . === Q.arq prefix i: <http://example/> prefix n: <http://example/ns#> select * where { ?x n:memberOf ?org . {{?x n:related ?y} minus {?y n:memberOf ?org}} } === which is: (prefix ((n: <http://example/ns#>) (i: <http://example/>)) (join (bgp (triple ?x n:memberOf ?org)) (minus (bgp (triple ?x n:related ?y)) (bgp (triple ?y n:memberOf ?org))))) >> arq.sparql --engine=ref --data D.ttl --query Q.arq --------------- | x | org | y | =============== --------------- because LHS of MINUS: prefix i: <http://example/> prefix n: <http://example/ns#> SELECT * {?x n:related ?y} ==> ------------------- | x | y | =================== | i:Jules | i:Jim | ------------------- and RHS of MINUS prefix i: <http://example/> prefix n: <http://example/ns#> SELECT * {?y n:memberOf ?org} ==> ------------------- | y | org | =================== | i:Jim | i:def | | i:Jules | i:abc | ------------------- so ?y=i:Jim in the LHS is in the RHS of the MINUS and so that row is removed from the results. The join with ?x n:memberOf ?org . is joining with the empty table so is empty. ---- What did you expect? What was the thought behind the question? Andy LHS = Left Hand Side RHS = Right Hand Side On 18/05/2010 1:57 PM, Olivier Corby wrote: > What is the result of this query ? > > i:Jules n:memberOf i:abc > i:Jules n:related i:Jim > i:Jim n:memberOf i:def > > select * where { > ?x n:memberOf ?org . > {{?x n:related ?y} minus {?y n:memberOf ?org}} > } > > > > Olivier > > > > > Please consider the environment before printing this email. > > Find out more about Talis at http://www.talis.com/ > shared innovation™ > > Any views or personal opinions expressed within this email may not be > those of Talis Information Ltd or its employees. The content of this > email message and any files that may be attached are confidential, and > for the usage of the intended recipient only. If you are not the > intended recipient, then please return this message to the sender and > delete it. Any use of this e-mail by an unauthorised recipient is > prohibited. > > Talis Information Ltd is a member of the Talis Group of companies and is > registered in England No 3638278 with its registered office at Knights > Court, Solihull Parkway, Birmingham Business Park, B37 7YB.
Received on Tuesday, 18 May 2010 13:43:25 UTC