_select!

# File activerecord/lib/active_record/relation/query_methods.rb, line 258
    def _select!(*fields) # :nodoc:
      fields.flatten!
      fields.map! do |field|
        klass.attribute_alias?(field) ? klass.attribute_alias(field).to_sym : field
      end
      self.select_values += fields
      self
    end