How many {convicted of} are to/by {drug possession} ?
Drug possession convictions effect how many people?
How many people are convicted of drug possession?
SELECT ( COUNT ( ?s ) AS ?d ) { ?s property:convicted_of resource:possession_of_a_controlled_substance }
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/P1399> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> http://wikidata.dbpedia.org/resource/Q1259959 .
} 

SELECT (COUNT(?sub) AS ?value ) { ?sub wdt:P1399 wd:Q1259959 }
17