which is the unit of frequency in the measurement system whose current density unit is ampere per square metre?
Entity Entity Entity Entity
m.03nsh m.02n9swl m.04j3wb3 g.121lm_nv
Hertz Megahertz Kilohertz Gigahertz
class class entity
measurement_unit.unit_of_frequency measurement_unit.measurement_system g.122rvtfy
measurement_unit.unit_of_frequency measurement_unit.measurement_system measurement_unit.current_density_unit
Unit of frequency Measurement System Ampere per square metre
none none none
measurement_unit.unit_of_frequency.measurement_system measurement_unit.measurement_system.current_density_units
Measurement system Current Density Units
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 :measurement_unit.unit_of_frequency . 
?x1 :type.object.type :measurement_unit.measurement_system . 
VALUES ?x2 { :g.122rvtfy } 
?x0 :measurement_unit.unit_of_frequency.measurement_system ?x1 . 
?x1 :measurement_unit.measurement_system.current_density_units ?x2 . 
FILTER ( ?x0 != ?x1 && ?x0 != ?x2 && ?x1 != ?x2  )
}
}
(AND measurement_unit.unit_of_frequency (JOIN measurement_unit.unit_of_frequency.measurement_system (JOIN measurement_unit.measurement_system.current_density_units g.122rvtfy)))