Question: Players from how many teams have participated in the National Hockey League?
SPARQL query:
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX prop: <http://dbpedia.org/property/>
PREFIX onto: <http://dbpedia.org/ontology/>
SELECT DISTINCT COUNT(?uri) WHERE { ?x prop:league <http://dbpedia.org/resource/National_Hockey_League> . ?x onto:team ?uri  . ?uri rdf:type onto:SportsTeam}