Question: Which presidents were born in 1945?
SPARQL:
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX onto: <http://dbpedia.org/ontology/>
PREFIX yago: <http://dbpedia.org/class/yago/>
SELECT DISTINCT ?uri ?string
WHERE 
{
	{
		?uri rdf:type onto:President .
		?uri onto:birthDate ?date .
		FILTER regex(?date,'^1945') .
                OPTIONAL {?uri rdfs:label ?string . FILTER (lang(?string) = 'en') }
	}
	UNION
	{
		?uri rdf:type yago:President.
		?uri onto:birthDate ?date .
		FILTER regex(?date, '^1945') .
                OPTIONAL {?uri rdfs:label ?string . FILTER (lang(?string) = 'en') }
	}
}