How many {architect} are for {St. Peter's Basilica} ?
What is the total number of architects that worked on St Peter's Basilica?
How many architects worked on the St. Peter's Basilica?
SELECT ( COUNT ( ?u ) AS ?i ) { resource:St._Peter's_Basilica property:architect ?u }
SELECT (COUNT(?obj) AS ?objs ) {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q12512> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P84> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?obj .
} 

SELECT (COUNT(?obj) AS ?value ) { wd:Q12512 wdt:P84 ?obj }
13