what is the {start time} for {Libya} has {member of} as {Arab League} ?
On which date did Libya become a member of Arab League?
When did Libya become a member of Arab League?
SELECT ?r WHERE { ?o property:start_time ?r . resource:Libya property:member_of ?o . ?o property:member_of resource:Arab_League }
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q1016> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P463> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q7172> .
?statement <http://www.wikidata.org/entity/P580> ?value. 
} 

SELECT ?value WHERE { wd:Q1016 p:P463 ?s . ?s ps:P463 wd:Q7172 . ?s pq:P580 ?value}