Question: How many people have been the head coach for Middlesbrough FC?
SPARQL:
SELECT DISTINCT COUNT(?uri) WHERE { ?x <http://dbpedia.org/property/club> <http://dbpedia.org/resource/Middlesbrough_F.C.> . ?x <http://dbpedia.org/ontology/manager> ?uri  . ?uri <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/Person>}