what is the {start time} for {Boston Red Sox} has {head coach} as {Jack Barry} ?
On what date did Jack Barry take over as the Head Coach of the Boston Red Sox?
When did Jack Barry take over as the Head Coach of the Boston Red Sox?
SELECT ?v WHERE { ?q property:head_coach resource:Jack_Barry . resource:Boston_Red_Sox property:head_coach ?q . ?q property:start_time ?v }
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q213959> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P286> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q6111176> .
?statement <http://www.wikidata.org/entity/P580> ?value. 
} 

SELECT ?value WHERE { wd:Q213959 p:P286 ?s . ?s ps:P286 wd:Q6111176 . ?s pq:P580 ?value}