An Error Was Encountered

Error Number: 1054

Unknown column 'specialprice' in 'where clause'

SELECT COUNT(vin) AS totalVehicles FROM inventory i WHERE i.active = 1 AND type = "new" AND make = "Buick" AND (CASE WHEN specialprice = "0" THEN sellingprice ELSE depsellingprice END) BETWEEN 20001 AND 30000