Question: Give me a list of all lakes in Denmark.
SPARQL:
PREFIX dbo: <http://dbpedia.org/ontology/>
PREFIX res: <http://dbpedia.org/resource/>
PREFIX yago: <http://dbpedia.org/class/yago/>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
SELECT DISTINCT ?uri ?string WHERE
{
	{ ?uri rdf:type dbo:Lake .
	  ?uri dbo:country res:Denmark . }
	UNION
	{ ?uri rdf:type yago:LakesOfDenmark . }
	OPTIONAL { ?uri rdfs:label ?string. FILTER (lang(?string) = 'en') }
}