Question: For how many different teams have the players debuted in Houston Astros played?
SPARQL query:
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX onto: <http://dbpedia.org/ontology/>
SELECT DISTINCT COUNT(?uri) WHERE { ?x onto:debutTeam <http://dbpedia.org/resource/Houston_Astros> . ?x onto:team ?uri  . ?uri rdf:type onto:SportsTeam}