How many {lake outflow} are to/by {Barents Sea} ?
Which is the number of lakes that outflow to the Barents Sea?4
How many lakes outflow to the Barents Sea?
SELECT ( COUNT ( ?g ) AS ?r ) { ?g property:lake_outflow resource:Barents_Sea }
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/P201> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> http://wikidata.dbpedia.org/resource/Q45823 .
} 

SELECT (COUNT(?sub) AS ?value ) { ?sub wdt:P201 wd:Q45823 }
10