what is the {date of birth} for {Pink} has {child} as {Willow Hart} ?
Willow Hart, daughter of Pink has a DOB of?
When was Pink's child, Willow Hart, born?
SELECT ?m WHERE { resource:Pink property:child ?u . ?u property:date_of_birth ?m . ?u property:child resource:Willow_Hart }
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q160009> .
?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/Q17378065> .
?statement <http://www.wikidata.org/entity/P569> ?value. 
} 

SELECT ?value WHERE { wd:Q160009 p:P40 ?s . ?s ps:P40 wd:Q17378065 . ?s pq:P569 ?value}