MySQL queries ..?

[Seapyramid]

This is the query I am using and it works great.

      $query = "SELECT * FROM `adopts_users` WHERE `username`='$loggedinname'";
      $result = mysql_query($query);
      $num = mysql_numrows($result);
      
      $i = 0;
      while ($i < $num) {
          $money = @mysql_result($result, $i, "money");
           $newbalance = $money - $cost;
          $i++;
      }
      mysql_query("UPDATE `adopts_users` SET `money`='" . $newbalance . "' WHERE `username`='$loggedinname'");

Sea