How many bands have members currently playing the Fender Stratocaster?
SELECT DISTINCT COUNT(?uri) WHERE { ?x <http://dbpedia.org/property/notableInstruments> <http://dbpedia.org/resource/Fender_Stratocaster> . ?uri <http://dbpedia.org/property/currentMembers> ?x  . ?uri <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/Band>}
Fender_Stratocaster