$sql = $azdb->get_row("SELECT * FROM ".$table_prefix."_content WHERE ID='".$_GET['ID']."'");

if($sql):

echo  '<h2>'.$sql->content_title.'</h2>';

echo  date('d m Y',strtotime($sql->content_modified));

echo  '<br />';

echo  $sql->content;

endif;



$sql = $azdb->get_results("SELECT * FROM ".$table_prefix."_content WHERE content_parent='".$_GET['ID']."'");

if($sql): foreach($sql as $sql):

echo  '<div class="comments">';

echo  '<h2>Main '.$sql->content_title.'</h2>';

echo  date('d m Y',strtotime($sql->content_modified));

echo  '<br />';

echo  $sql->content;

echo  '<br />';




$sql1 = $azdb->get_results("SELECT * FROM ".$table_prefix."_content WHERE content_parent='".$sql->ID."'");

if($sql1): foreach($sql1 as $sql1):

echo  '<div class="comments">';

echo  '<h2>'.$sql1->ID.' - '.$sql1->content_title.'</h2>';

echo  date('d m Y',strtotime($sql1->content_modified));

echo  '<br />';

echo  $sql1->content;

$sql2 = $azdb->get_results("SELECT * FROM ".$table_prefix."_content WHERE content_parent='".$sql1->ID."' ");

if($sql2): foreach($sql2 as $sql2):

echo  '<div class="comments">';

echo  '<h2>'.$sql2->content_title.'</h2>';

echo  date('d m Y',strtotime($sql2->content_modified));

echo  '<br />';

echo  $sql2->content;

echo  '</div>';

endforeach; endif;

echo  '</div>';

endforeach; endif;

echo  '</div>';

endforeach; endif;

$id = isset($_GET['id']) ? $_GET['id'] : 0;
$root_sql = $azdb->get_results("SELECT * FROM categories WHERE cat_parent = " . $id);

recursive_categories($root_sql);

function recursive_categories($results)
{
     if(count($results))
     {
         echo "<ul>";
         foreach($results as $res)
         {
             echo "<li>" . $res->category;
             //Rest of what ever you want to do with each row

             //Check this category for children
             $rows = $azdb->get_results("SELECT * FROM categories WHERE cat_parent  = " . $res->id);

             recursive_categories($rows);

             //has to be after the inner loops
             echo "</li>";
         }
         echo "</ul>";
     }
}

1 - main
1.1 - comment 1
1.2 - comment 2
1.2.1 - nested comment for comment 2
1.2.1.1 - nested comment for comment 2, nested comment 1
1.2.2
1.2.3
1.2.2.1
1.1.1 - (this comment you could order by your sql call to be 3rd from the top, etc)