Question: Which countries have places with more than two caves?
SPARQL:
PREFIX dbo: <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#>
SELECT DISTINCT ?uri ?string 
WHERE {       
        ?cave rdf:type dbo:Cave . 
        ?cave dbo:location ?uri .
        ?uri rdf:type dbo:Country .
        OPTIONAL { ?uri rdfs:label ?string. FILTER (lang(?string) = 'en') }
} 
GROUP BY ?uri ?string
HAVING (COUNT(?cave) > 2)