what is the {start time} for {Liv Tyler} has {partner} as {Joaquin Phoenix} ?
When did Liv Tyler date Joaquin Phoenix?
When was Liv Tyler in a relationship with Joaquin Phoenix?
SELECT ?t WHERE { ?r property:unmarried_partner resource:Joaquin_Phoenix . resource:Liv_Tyler property:unmarried_partner ?r . ?r property:start_time ?t }
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q168763> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P451> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q185140> .
?statement <http://www.wikidata.org/entity/P580> ?value. 
} 

SELECT ?value WHERE { wd:Q168763 p:P451 ?s . ?s ps:P451 wd:Q185140 . ?s pq:P580 ?value}