rocket engine is the category for which engines?
Entity Entity Entity Entity Entity Entity Entity Entity
m.02qfd20 m.032blg m.034_44 m.0523nd9 m.07_3lln m.07dk1d m.07kfw0m m.0d7qdq
Walter HWK 109-509 Space Shuttle main engine Rocketdyne F-1 RD-0410 RD-0750 RD-180 RD-0146 de Havilland Spectre
class entity
engineering.engine m.01mx49
engineering.engine engineering.engine_category
Engine Rocket engine
none none
engineering.engine.category
Category
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 :engineering.engine . 
VALUES ?x1 { :m.01mx49 } 
?x0 :engineering.engine.category ?x1 . 
FILTER ( ?x0 != ?x1  )
}
}
(AND engineering.engine (JOIN engineering.engine.category m.01mx49))