How many {instrument} are for {Moby} ?
What instruments does the musician Moby use?
How many instruments does Moby play?
SELECT ( COUNT ( ?x ) AS ?l ) { resource:Moby property:instrument ?x }
SELECT (COUNT(?obj) AS ?objs ) {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q14045> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P1303> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?obj .
} 

SELECT (COUNT(?obj) AS ?value ) { wd:Q14045 wdt:P1303 ?obj }
5