How to Programmaticly Do Infinite Recursion With PHP

I have a list of questions. Each question can have children and children can also have children. My database is set up as follows:

id: incrementing id, question: string, parentId: integer, industryId: integer

So basically when i save a parent level question it goes in with a parent ID of "0". If that question was saved as id = 1. Then the sub child would be parentId = 1 and so on.

I need to infinitely loop through the products array to determine if there are more children, but i can't figure out a way to do it that is not manual. Here is my code:

<?php
        //Does this question have sub questions?
        $hasChildren = FALSE;
        foreach($questions as $q) {
            if($q->parentId === $question->id) {
                $hasChildren = TRUE;
            }
        }
        if($hasChildren === TRUE): 
        $unique = uniqid();
        ?>
        <ul class="sub-list-{{$unique}}">
            @foreach($questions as $q)
            @if($q->parentId === $question->id)
            <li>{{$q->question}}

                <?php
                //Does this question have sub questions?
                $hasChildren = FALSE;
                foreach($questions as $q1) {
                    if($q1->parentId === $q->id) {
                        $hasChildren = TRUE;
                    }
                }
                if($hasChildren === TRUE): 
                $unique = uniqid();
                ?>
                <ul class="sub-list-{{$unique}}">
                    @foreach($questions as $q1)
                    @if($q1->parentId === $q->id)
                    <li>{{$q1->question}}

                    </li>
                    @endif
                    @endforeach
                </ul>
                <?php endif; ?>

            </li>
            @endif
            @endforeach
        </ul>
        <?php endif; ?>

via Chebli Mohamed