How many {health specialty} are to/by {clinical psychology} ?
Clinical psychology covers what healthy specialty?
What health specialty does clinical psychology cover?
SELECT ( COUNT ( ?u ) AS ?k ) { ?u property:health_specialty resource:clinical_psychology }
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/P1995> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> http://wikidata.dbpedia.org/resource/Q199906 .
} 

SELECT (COUNT(?sub) AS ?value ) { ?sub wdt:P1995 wd:Q199906 }
42