In a FILTER ">" (biger that) is not accepted.
Example:
FILTER (xsd:dateTime(?start) < xsd:dateTime("2008-01-26T23:59:59Z")) works fine but
FILTER (xsd:dateTime(?start) > xsd:dateTime("2008-01-26T23:59:59Z")) causes the following error:
Fatal error: Uncaught exception 'SparqlEngineDb_SqlGeneratorException' with message 'Unsupported tree type: ' in /home/space/vernkirche/htdocs/sw/includes/rdfapi-php/api/sparql/SparqlEngineDb/FilterGenerator.php:124 Stack trace: #0 /home/space/vernkirche/htdocs/sw/includes/rdfapi-php/api/sparql/SparqlEngineD....