How many {medical examinations} are to/by {magnetic resonance imaging} ?
How many examinations have been performed by MRI?
How many medical examinations have been done by magnetic resonance imaging?
SELECT ( COUNT ( ?t ) AS ?c ) { ?t property:medical_examinations resource:magnetic-resonance_imaging }
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/P923> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> http://wikidata.dbpedia.org/resource/Q161238 .
} 

SELECT (COUNT(?sub) AS ?value ) { ?sub wdt:P923 wd:Q161238 }
27