The following issue has been SUBMITTED. ====================================================================== http://bugs.librdf.org/mantis/view.php?id=407 ====================================================================== Reported By: vermonster Assigned To: ====================================================================== Project: Redland librdf RDF API Issue ID: 407 Category: query engine Reproducibility: always Severity: major Priority: normal Status: new ====================================================================== Date Submitted: 2010-12-21 14:45 Last Modified: 2010-12-21 14:45 ====================================================================== Summary: ORDER BY does not appear to handle undefined values correctly Description: According to the SPARQL spec,
SPARQL ... fixes an order between some kinds of RDF terms that would not otherwise be ordered: (Lowest) no value assigned to the variable or expression in this solution. Blank nodes IRIs RDF literals However, I am noticing if I do a SPARQL query where I specify ORDER BY (?x), and ?x is defined using an OPTIONAL clause, so it is not always bound, then the tuples for which ?x is undefined always appear first in the SPARQL output, irrespective of whether I do an ORDER BY (?x) or ORDER BY DESC(?x). If I do an ORDER BY ?x, then they should appear first; if I do an ORDER BY DESC(?x), then they should appear last. Steps to Reproduce: Please see description. ====================================================================== Issue History Date Modified Username Field Change ====================================================================== 2010-12-21 14:45 vermonster New Issue ====================================================================== _______________________________________________ redland-dev mailing list [email protected] http://lists.librdf.org/mailman/listinfo/redland-dev
