module Geocoder::Store::ActiveRecord::ClassMethods

def distance_sql(latitude, longitude, options = {})


capabilities (trig functions?).
SQL for calculating distance based on the current database's
#
def distance_sql(latitude, longitude, options = {})
  method_prefix = using_unextended_sqlite? ? "approx" : "full"
  Geocoder::Sql.send(
    method_prefix + "_distance",
    latitude, longitude,
    full_column_name(options[:latitude] || geocoder_options[:latitude]),
    full_column_name(options[:longitude]|| geocoder_options[:longitude]),
    options
  )
end