public function select($table, $fields = [], array $where = [], array $order = [], int $start = 0): ?\stdClass
  {
    $args = $this->_add_kind($this->_set_limit_1(\func_get_args()));
    if ( $r = $this->_exec(...$args) ){
      return $r->get_object();
    }
    return null;
  }