Can't get ID

if (isset($_POST['delete'])) {
   $result = dbquery("DELETE FROM ".DB_GRIMS_BLOG_COMMENTS." WHERE comment_id='".$_POST['comment_id']."'");
   $result1 = dbquery("UPDATE ".DB_GRIMS_BLOG_POST." SET comments=comments-1 WHERE post_id ='".$_GET['my_id']."'");

   echo "<table align='center' width='100%' border='0' class='mytable'><tr>n";
   echo "<td align='center'><b>".$locale['gb_131']."</b></td>n";
   echo "</tr></table>n";
exit();
}
// Select comment to edit
   echo "<div style='text-align:center'><h5><b>Select A Comment To Edit Or Delete</b></h5><br /><br /></div>n";
   $editlist = ""; $sel = "";
   $result = dbquery("SELECT * FROM ".DB_GRIMS_BLOG_COMMENTS." ORDER BY comment_id DESC");
   if (dbrows($result) != 0) {
      while ($data = dbarray($result)) {
      $result1 = dbquery("SELECT post_id, post_title FROM ".DB_GRIMS_BLOG_POST." WHERE post_id='".$data['post_id']."'");
         while ($stuff = dbarray($result1)) {
         $my_id = $stuff['post_id'];
         $post = $stuff['post_title'];
         }
    if (isset($_POST['comment_id']) && isnum($_POST['comment_id'])) {
          $sel = ($_POST['comment_id'] == $data['comment_id'] ? " selected" : "");
         }
         $editlist .= "<option value='".$data['comment_id']."'$sel>".$data['name']." - $post - $my_id</option>n";
      }
   echo "<div style='text-align:center'>n";
   echo "<form id='edit_select' name='edit_select' method='post' action='".FUSION_SELF."'>n";
   echo "<b>Comment: </b><select id='comment_id' name='comment_id' class='textbox' style='width:350px;'>".$editlist."</select>n";
   echo "<input class='button' type='submit' name='edit' value='".$locale['gb_161']."' />n";
   echo "</form><br /><br />n";
   echo "</div>n";
}