How many {publication date} are for {Forrest Gump} ?
In what year did Forrest Gump come out?
When was Forrest Gump publication date
SELECT ( COUNT ( ?z ) AS ?p ) { resource:Forrest_Gump property:publication_date ?z }
SELECT (COUNT(?obj) AS ?objs ) {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q134773> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P577> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?obj .
} 

SELECT (COUNT(?obj) AS ?value ) { wd:Q134773 wdt:P577 ?obj }
5