# File lib/active_record/relation/calculations.rb, line 179
    def pluck(column_name)
      if column_name.is_a?(Symbol) && column_names.include?(column_name.to_s)
        column_name = "#{connection.quote_table_name(table_name)}.#{connection.quote_column_name(column_name)}"
      else
        column_name = column_name.to_s
      end

      relation = clone
      relation.select_values = [column_name]
      klass.connection.select_all(relation.arel).map! do |attributes|
        klass.type_cast_attribute(attributes.keys.first, klass.initialize_attributes(attributes))
      end
    end