how many nebula's have an apparent magnitude of 15.0?
Value
2
class literal
astronomy.nebula 15.0^^http://www.w3.org/2001/XMLSchema#float
astronomy.nebula type.float
Nebula 15.0
count none
astronomy.celestial_object.magnitude
Apparent Magnitude
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 (COUNT(?x0) AS ?value) WHERE {
SELECT DISTINCT ?x0  WHERE { 
?x0 :type.object.type :astronomy.nebula . 
VALUES ?x1 { "15.0"^^<http://www.w3.org/2001/XMLSchema#float> } 
?x0 :astronomy.celestial_object.magnitude ?x1 . 
FILTER ( ?x0 != ?x1  )
}
}
(COUNT (AND astronomy.nebula (JOIN astronomy.celestial_object.magnitude 15.0^^http://www.w3.org/2001/XMLSchema#float)))