what is the {start time} for {Grenoble} has {head of government} as {Éric Piolle} ?
What was the timeframe that Eric Piolle was the Head of the Government of Grenoble?
When was Eric Piolle the the Head of Government of Grenoble?
SELECT ?x WHERE { ?w property:head_of_government resource:Éric_Piolle . resource:Grenoble property:head_of_government ?w . ?w property:start_time ?x }
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q1289> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P6> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q16007948> .
?statement <http://www.wikidata.org/entity/P580> ?value. 
} 

SELECT ?value WHERE { wd:Q1289 p:P6 ?s . ?s ps:P6 wd:Q16007948 . ?s pq:P580 ?value}