SPARQL: Optional

Semantic Web Technologies: XML, RDF, OWL

To optionally match: (get more info back if it is there)

PREFIX foaf: <http://xmlns.com/foaf/0.1/>
SELECT ?name ?depiction
WHERE { 
        ?person foaf:name ?name .
        OPTIONAL {
            ?person foaf:depiction ?depiction .
        } .
      }