Category Hierarchy (PHP/MySQL)

Question

I am trying to get my all categories and sub-categories from MySQL database in a hierarchy:

My result should be like that (just example):

Answer 1

@Amnon Your code works perfectly. Just tested it with CodeIgniter and it worked like a charm. Here's the working code if anyone needs it:

parent_id;
    $id   = $cat->cat_id;
    $name = $cat->cat_name;

    // Create or add child information to the parent node
    if (isset($tree[$pid]))
        // a node for the parent exists
        // add another child id to this parent
        $tree[$pid]["children"][] = $id;
    else
        // create the first child to this parent
        $tree[$pid] = array("children"=>array($id));

    // Create or add name information for current node
    if (isset($tree[$id]))
        // a node for the id exists:
        // set the name of current node
        $tree[$id]["name"] = $name;
    else
        // create the current node and give it a name
        $tree[$id] = array( "name"=>$name );
}
return $tree;
}


function toUL($tree, $id, $html){
  $html .= '
'.PHP_EOL;

  if (isset($tree[$id]['name']))
    $html .= '
' . $tree[$id]['name'];

  if (isset($tree[$id]['children']))
  {
    $arChildren = &$tree[$id]['children'];
    $len = count($arChildren);
    for ($i=0; $i<$len; $i++) {
        $html .= toUL($tree, $arChildren[$i], "");
    }
    $html .= '
'.PHP_EOL;
  }

  $html .= '
'.PHP_EOL;
  return $html;
}

$tree = disTree($all_cats);
// Display the tree
echo toUL($tree, 0, "");

?>

The only thing I changed was adding my own array ($all_cats).