Question: I need to change the iframe url from the same iframe.
For example: "**<http://parent.com>**" is the Parent Domain URL of my website with an http
and: "**<https://iframe.com>**" is the iframe Domain URL with an https. The two domains are different. 

Here's the code of the parent window:

```
  <html>
    <head>
      <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
      <script>
        function sheck19()
        {
          document.getElementById("myFrame19").height="700";
          document.getElementById('myFrame19').src="https://iframe.com/home.php";
        }
      </script>
    </head>
    <body>
        <iframe id="myFrame19" src="https://iframe.com/index.php" width="620" height="410" frameborder="0"></iframe>
    </body>
  </html>

```

and here's the code of the iframe document:

```
<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

    <script type="text/javascript">
      function uuui() {
        window.parent.sheck19();
      };
    </script>
  </head>

  <body>
    <input  name="Continuer" type="submit" value="Continuer" onclick="uuui();">
  </body>

</html>

```

Answer: 
You can achieve this using NOT EXISTS and MEMBER OF. Something like this

```
$qb->select('q.question_id, q.question_intitule')
    ->from('MyBundleNameSpace\Entity\Question', 'q')
    ->where('NOT EXISTS (SELECT 1 FROM MyBundleNameSpace\Entity\Jouer j WHERE j MEMBER OF q.jouers)');

```
Thank you for your answer FuzzyTree! It works!
I had adapted it in order to put it into my QuestionRepository.

Here is my method:

```
public function findNotAnsweredByJoueurs(Partie $partie, $level)
{
    $qb = $this->createQueryBuilder('q');
    $qb->where('q.level < ' . $level);
    foreach($partie->getJoueurs() as $joueur)
    {
        $qb->andWhere('NOT EXISTS (SELECT ' . $joueur->getId() . ' FROM Cloud\Bundle\MoneyDropBundle\Entity\Joueur j WHERE j MEMBER OF q.joueurs)');
    }

    return $qb->getQuery()
              ->getResult();
}

```