How many {operator} are to/by {Greenpeace} ?
Give me the name of the operator of Greenpeace.
Who operates Greenpeace?
SELECT ( COUNT ( ?t ) AS ?k ) { ?t property:operator resource:Greenpeace }
SELECT (COUNT(?sub) AS ?subs ) {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> ?sub .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P137> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> http://wikidata.dbpedia.org/resource/Q81307 .
} 

SELECT (COUNT(?sub) AS ?value ) { ?sub wdt:P137 wd:Q81307 }
7