How many {field of this occupation} are to/by {art history} ?
In the field of art history how many occupations are there?
How many occupations are in the field of art history?
SELECT ( COUNT ( ?l ) AS ?z ) { ?l property:field_of_this_occupation resource:art_history }
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/P425> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> http://wikidata.dbpedia.org/resource/Q50637 .
} 

SELECT (COUNT(?sub) AS ?value ) { ?sub wdt:P425 wd:Q50637 }
1