How many {lakes on river} are for {Tagus river} ?
What is the number of lakes in the Tagus river?
How make lakes are in Tagus river?
SELECT ( COUNT ( ?l ) AS ?x ) { resource:Tagus_river property:lakes_on_river ?l }
SELECT (COUNT(?obj) AS ?objs ) {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q14294> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P469> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?obj .
} 

SELECT (COUNT(?obj) AS ?value ) { wd:Q14294 wdt:P469 ?obj }
8