$query = mysql_query("SELECT * FROM blah WHERE 1");
$rows = array();
if (mysql_num_rows($query))
{
     $i = 0;
     while ($row = mysql_fetch_assoc($query))
     {
          $row = array_unshift($row, "index" => $i);
          $rows[] = $row;
          
          $i++;
     }
}