Question: Which monarchs of the United Kingdom were married to a German?
SPARQL:
PREFIX yago: <http://dbpedia.org/class/yago/>
PREFIX onto: <http://dbpedia.org/ontology/>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX res: <http://dbpedia.org/resource/>
SELECT DISTINCT ?uri ?string
WHERE 
{
        ?uri rdf:type yago:MonarchsOfTheUnitedKingdom .
        { ?uri onto:spouse ?spouse . } UNION { ?spouse onto:spouse ?uri . }
        ?spouse onto:birthPlace res:Germany.
        OPTIONAL {?uri rdfs:label ?string. FILTER (lang(?string) = 'en') }
}