I would want to know how I can display the result from a soql child to parent request?
**My request is:**

    $query = "SELECT FirstName, LastName, (select Retreat_Booking__c.Retreat__c from Retreat_Bookings__r)FROM Contact";
    $response = $mySforceConnection->query($query);
  

    $queryResult = new QueryResult($response);
    while($queryResult->current()->FirstName!='' || $queryResult->current()->LastName!='')
    {
        echo $queryResult->current()->FirstName." ".$queryResult->current()->LastName." ".$queryResult->current()-> Retreat_Bookings__r->Retreat_Booking__c->Retreat__c." <BR/>";
        $queryResult->next();
    }
The request works and display **FirstName** and **LastName** but not **Retreat__c**. I know the result in the 2nd select is a json and I tried many things, but nothing works.

Is somebody can help me please?
Thanks a lot in advance!!