<?php
$username = 'nmarp';
$password = '';

mysql_connect('localhost',$username,$password);

mysql_select_db('nmarp');

$query = "SELECT purchasePrice
          FROM code
          WHERE id
          IN (SELECT DISTINCT codeId FROM codeValidationChangelog
          WHERE status = 'Closed: Check Approved')";

$result = mysql_query($query);

$total = 0;
while ($row = mysql_fetch_array($result)) {
    $row['purchasePrice'] = preg_replace('/[^\d\.]/', '', $row['purchasePrice']);
    $purchasePrice = (float)$row['purchasePrice'];
    $purchasePrice = trim($purchasePrice);
    $purchasePrice = sprintf('%.2f', $purchasePrice);

    $total += $purchasePrice;
}
echo $total . PHP_EOL;