What is {child} of {Frederick William I of Prussia} and {date of birth}
Who used to be Frederick William I of Prussia's child and what is the date of their birth?
Who was Frederick William I of Prussia's child and what is the date of their birth?
SELECT ?v ?p WHERE { ?x property:child ?p . resource:Frederick_William_I_of_Prussia property:child ?x . ?x property:date_of_birth ?v . }
select distinct ?dataprop1 ?obj where { ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q105013> . ?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> ?obj . ?statement <http://www.wikidata.org/entity/P580> ?dataprop1 . } 
SELECT ?value1 ?obj WHERE { wd:Q105013 p:P40 ?s . ?s ps:P40 ?obj . ?s pq:P569 ?value1 . }