dart 18 class is of which ship type?
Entity Entity
m.062z98q m.01bvgh
Sailing Dinghy Catamaran
class entity
boats.ship_type m.04gvmxf
boats.ship_type boats.ship_class
Ship type Dart 18
none none
boats.ship_type.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_type . 
VALUES ?x1 { :m.04gvmxf } 
?x0 :boats.ship_type.ship_class ?x1 . 
FILTER ( ?x0 != ?x1  )
}
}
(AND boats.ship_type (JOIN boats.ship_type.ship_class m.04gvmxf))