code: public function asStatement()
    {
      return 'SELECT ' . $this->prepareColumns() . ' FROM ' . $this->prepareTable()
        . $this->prepareJoin()
        . $this->prepareWhere(false)
        . $this->prepareGroupBy()
        . $this->prepareHaving(false)
        . $this->prepareOrderBy()
        . $this->prepareLimit();
    }
docs: Создать выражение с подстановкой переменных