How many {producer} are to/by {Hal B. Wallis} ?
In regards to Hal B. Wallis, how many producers are there?
How many producers are by Hal B. Wallis?
SELECT ( COUNT ( ?x ) AS ?k ) { ?x property:producer resource:Hal_B._Wallis }
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/P162> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> http://wikidata.dbpedia.org/resource/Q472520 .
} 

SELECT (COUNT(?sub) AS ?value ) { ?sub wdt:P162 wd:Q472520 }
208