How many {depositor} are to/by {United Nations Secretary-General} ?
Who are the depositors with the United Nations Secretary-General?
How many depositors are with the {United Nations Secretary-General} ?
SELECT ( COUNT ( ?z ) AS ?u ) { ?z property:depositor resource:Secretary-General_of_the_United_Nations }
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/P2058> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> http://wikidata.dbpedia.org/resource/Q81066 .
} 

SELECT (COUNT(?sub) AS ?value ) { ?sub wdt:P2058 wd:Q81066 }
65