How many {patent number} are for {MP3} ?
Which is the patent number for MP3?
What's the patent number for MP3?
SELECT ( COUNT ( ?l ) AS ?t ) { resource:MP3 property:patent_number ?l }
SELECT (COUNT(?obj) AS ?objs ) {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q42591> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P1246> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?obj .
} 

SELECT (COUNT(?obj) AS ?value ) { wd:Q42591 wdt:P1246 ?obj }
5