the hub for merlin express is located at which airport?
Entity
m.019dkm
Rafael Hernández Airport
class entity
aviation.airport m.02pywxs
aviation.airport aviation.airline
Airport Merlin Express
none none
aviation.airport.hub_for
Hub for
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> PREFIX : <http://rdf.freebase.com/ns/> 
SELECT (?x0 AS ?value) WHERE {
SELECT DISTINCT ?x0  WHERE { 
?x0 :type.object.type :aviation.airport . 
VALUES ?x1 { :m.02pywxs } 
?x0 :aviation.airport.hub_for ?x1 . 
FILTER ( ?x0 != ?x1  )
}
}
(AND aviation.airport (JOIN aviation.airport.hub_for m.02pywxs))