SQLBuilder\Universal\Syntax\AlterTableAdd::toSql PHP Метод

    public function toSql(BaseDriver $driver, ArgumentArray $args)
    {
        if ($this->subquery instanceof ToSqlInterface) {
            return 'ADD ' . $this->subquery->toSql($driver, $args);
        }
        return 'ADD ' . $this->subquery;
    }