How many {distribution} are to/by {printed circuit board} ?
A printed circuit board has how many distributions?
How many distributions are there of a printed circuit board?
SELECT ( COUNT ( ?x ) AS ?t ) { ?x property:distribution_format resource:printed_circuit_board }
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/P437> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> http://wikidata.dbpedia.org/resource/Q173350 .
} 

SELECT (COUNT(?sub) AS ?value ) { ?sub wdt:P437 wd:Q173350 }
5