find the ships of class buckley-class destroyer escort.
Entity Entity Entity Entity Entity
m.08rq10 m.0ch77c m.03m9tr2 m.0dz1tn m.08xdmk
USS Holton USS England (DE-635) USS Hollis USS Laning USS Cronin
class entity
boats.ship m.05nkrj
boats.ship boats.ship_class
Ship Buckley-class destroyer escort
none none
boats.ship.ship_class
Ship Class
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 :boats.ship . 
VALUES ?x1 { :m.05nkrj } 
?x0 :boats.ship.ship_class ?x1 . 
FILTER ( ?x0 != ?x1  )
}
}
(AND boats.ship (JOIN boats.ship.ship_class m.05nkrj))