what is the {point in time} for {Wayne Gretzky} has {award received} as {Hockey Hall of Fame} ?
When did Wayne Gretzy get put into the Hockey hall of fame?
When was Wayne Gretzky inducted intot the Hockey Hall of Fame?
SELECT ?t WHERE { ?w property:point_in_time ?t . resource:Wayne_Gretzky property:award_received ?w . ?w property:award_received resource:Hockey_Hall_of_Fame }
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q209518> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P166> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q1136687> .
?statement <http://www.wikidata.org/entity/P585> ?value. 
} 

SELECT ?value WHERE { wd:Q209518 p:P166 ?s . ?s ps:P166 wd:Q1136687 . ?s pq:P585 ?value}