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https://issues.apache.org/jira/browse/JENA-750?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14074898#comment-14074898
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Andy Seaborne commented on JENA-750:
------------------------------------
Actually, the answer is right!
The OntModel is irrelevant.
{noformat}
SELECT ?resource (count(?c) AS ?count)
{ ?resource <http://xmlns.com/foaf/0.1/age> ?c }
GROUP BY ?resource
{noformat}
One row, resource unbound, count of zero. When count is zero, there is one row
with no key to return the zero count.
So if you add
{noformat}
HAVING ( count(?c) != 1 )
{noformat}
the row passes that test.
You have projected away the count column (by using {{HAVING ( count(?c) != 1
)}}).
> Inconsistent state of QuerySolution
> -----------------------------------
>
> Key: JENA-750
> URL: https://issues.apache.org/jira/browse/JENA-750
> Project: Apache Jena
> Issue Type: Bug
> Components: Jena
> Affects Versions: Jena 2.11.1
> Environment: Ubuntu 14.02
> Reporter: Dimitris Kontokostas
>
> Steps to reproduce:
> 1) create an ontology Model
> {code}
> ModelFactory.createOntologyModel(OntModelSpec.OWL_DL_MEM,
> ModelFactory.createDefaultModel());
> {code}
> 2) read the following URI: http://dbpedia.org/resource/Berlin
> with model.read()
> 3) run this query against the model
> {code}
> SELECT DISTINCT ?resource
> WHERE
> { ?resource <http://xmlns.com/foaf/0.1/age> ?c }
> GROUP BY ?resource
> HAVING ( count(?c) != 1 )
> {code}
> ===================
> "resource" variable does not exists in the query solution and I get a
> NullPointerException
> {code}
> while (results.hasNext()) {
> QuerySolution qs = results.next();
> String resource = qs.get("resource").toString();
> }
> {code}
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