PREFIX foaf: <http://xmlns.com/foaf/0.1/>
PREFIX ex: <http://ns.example.org/#>

SELECT ?x ?hpage ?name ?mbox ?age ?blurb ?friend
FROM <data.n3>
WHERE { ?x foaf:name ?name .
        ?x foaf:mbox ?mbox .
        ?x foaf:homepage ?hpage .
        ?x foaf:knows ?friend .
        OPTIONAL { ?x ex:ageInYears ?age } .
        OPTIONAL { ?x ex:blurb ?blurb }
      }
ORDER BY ?name