jena-arq/testing/DAWG-Final/expr-builtin/q-str-4.rq

PREFIX  xsd: <http://www.w3.org/2001/XMLSchema#>
PREFIX  : <http://example.org/things#>
SELECT  ?x ?v
WHERE
    { ?x :p ?v . 
      FILTER ( str(?v) = ""  ) .
    }