phql intermediate representation

Hello i have a query column like with the query builder

$query = new \Phalcon\Mvc\Model\Query\Builder();
$query->columns("CONCAT('_auth_user.id','_auth_user.login') as grid_action");
$arr = $query->getQuery()->parse();

In the array i have the intermediate representation of the PHQL statement.

is it possible to translate the array back in a normale string? I know i can tranlsate it back to a normal phql like

$this->query->getQuery()->setIntermediate($sqlColumns)->setType(Model\Query::TYPE_SELECT)->getSql()['sql']

but thats only working if i have to complete intermediate representation array but i just wanna translate the column to back to a string.

array (size=4)
'type' => string 'scalar' (length=6)
  'column' => 
    array (size=3)
      'type' => string 'functionCall' (length=12)
      'name' => string 'CONCAT' (length=6)
      'arguments' => 
        array (size=2)
          0 => 
            array (size=4)
              'type' => string 'qualified' (length=9)
              'domain' => string '_auth_user' (length=10)
              'name' => string 'id' (length=2)
              'balias' => string 'id' (length=2)
          1 => 
            array (size=4)
              'type' => string 'qualified' (length=9)
              'domain' => string '_auth_user' (length=10)
              'name' => string 'login' (length=5)
              'balias' => string 'login' (length=5)
  'balias' => string 'grid_action' (length=11)
  'sqlAlias' => string 'grid_action' (length=11)

thanks for your help, pat