what is the {start time} for {Elon Musk} has {spouse} as {Justine Musk} ?
On what date did Elon Musk marry his wife Justine Musk?
When did Elon Musk marry his spouse Justine Musk?
SELECT ?b WHERE { ?z property:spouse resource:Justine_Musk . ?z property:start_time ?b . resource:Elon_Musk property:spouse ?z }
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q317521> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P26> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q6318376> .
?statement <http://www.wikidata.org/entity/P580> ?value. 
} 

SELECT ?value WHERE { wd:Q317521 p:P26 ?s . ?s ps:P26 wd:Q6318376 . ?s pq:P580 ?value}