PREFIX foaf:
PREFIX ex:
SELECT ?x ?hpage ?name ?mbox ?age ?blurb ?friend
FROM
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