Question: What postcode is shared by London and Chelsea?
Answer(s):
answer: SW3 6RS

SPARQL query:
PREFIX ns: <http://rdf.freebase.com/ns/>
SELECT DISTINCT ?x
WHERE {
FILTER (?x != ns:m.04jpl)
FILTER (!isLiteral(?x) OR lang(?x) = '' OR langMatches(lang(?x), 'en'))
ns:m.04jpl ns:location.citytown.postal_codes ?x .
?x ns:location.location.containedby ns:m.01t21q . 
}