How many {student of} are for {Wilhelm Furtwängler} ?
Which is the number of students that are studying in the Wilhelm Furtwängler?
How many students are studying in the {Wilhelm Furtwängler} ?
SELECT ( COUNT ( ?x ) AS ?e ) { resource:Wilhelm_Furtwängler property:student_of ?x }
SELECT (COUNT(?obj) AS ?objs ) {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q57285> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P1066> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?obj .
} 

SELECT (COUNT(?obj) AS ?value ) { wd:Q57285 wdt:P1066 ?obj }
4