# File lib/active_record/calculations.rb, line 117
      def calculate(operation, column_name, options = {})
        validate_calculation_options(operation, options)
        column_name     = options[:select] if options[:select]
        column_name     = '*' if column_name == :all
        column          = column_for column_name
        catch :invalid_query do
          if options[:group]
            return execute_grouped_calculation(operation, column_name, column, options)
          else
            return execute_simple_calculation(operation, column_name, column, options)
          end
        end
        0
      end