what is the {date of death} for {Louis IX of France} has {child} as {Peter, Count of Perche and Alençon} ?
When did Peter, Count of Perche and Alencon, son of Louis IX of France, die?
What is the death date of Peter, Count of Perche and Alençon, the son of Louis IX of France?
SELECT ?x WHERE { ?c property:child resource:Peter,_Count_of_Perche_and_Alençon . ?c property:date_of_death ?x . resource:Louis_IX_of_France property:child ?c }
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q346> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P40> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q739327> .
?statement <http://www.wikidata.org/entity/P570> ?value. 
} 

SELECT ?value WHERE { wd:Q346 p:P40 ?s . ?s ps:P40 wd:Q739327 . ?s pq:P570 ?value}