Question: How many players debuted their careers from San Francisco 49ers?
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 {?uri onto:debutTeam <http://dbpedia.org/resource/San_Francisco_49ers>  . ?uri rdf:type onto:Athlete}