Development: Missing subtotal

If I'm correct, the sub total (total without tax) is still missing.
Please add the following line into the sql_queries.php file:
$invoice['subtotal'] = number_format(getInvoiceTotal($invoice['id'],'false'),2);
on line 487 right after:
$invoice['total'] = getInvoiceTotal($invoice['id']);

This gives people the option to show the total without tax.

Herewith the two updated functions of the sql_queries.php

getInvoices
function getInvoice($id) {

global $config;

$sql = "SELECT * FROM ".TB_PREFIX."invoices WHERE id = $id";
//echo $sql;

$query = mysqlQuery($sql) or die(mysql_error());

//print_r($query);
$invoice = mysql_fetch_array($query);

//print_r($invoice);
//exit();

$invoice['date'] = date( $config['date_format'], strtotime( $invoice['date'] ) );
$invoice['calc_date'] = date('Y-m-d', strtotime( $invoice['date'] ) );
$invoice['total'] = getInvoiceTotal($invoice['id']);
$invoice['subtotal'] = getInvoiceTotal($invoice['id'],'false');
$invoice['total_format'] = round($invoice['total'],2);
$invoice['paid'] = calc_invoice_paid($invoice['id']);
$invoice['paid_format'] = round($invoice['paid'],2);
$invoice['owing'] = $invoice['total'] - $invoice['paid'];
$invoice['total_tax'] = $invoice['total'] - $invoice['subtotal'];

return $invoice;
}
I cleaned the total tax calculation also, this saves a query again. Good for the speed! ;)

getInvoiceTotal
function getInvoiceTotal($invoice_id, $tax='true') {
global $LANG;

if ($tax=='true') {
$sql ="SELECT SUM(total) AS total FROM ".TB_PREFIX."invoice_items WHERE invoice_id = $invoice_id";
$query = mysqlQuery($sql);
$res = mysql_fetch_array($query);
} else {
$sql ="SELECT SUM(total) AS total, SUM(tax_amount) AS total_tax FROM ".TB_PREFIX."invoice_items WHERE invoice_id = $invoice_id";
$query = mysqlQuery($sql);
$res = mysql_fetch_array($query);
$res['total'] = $res['total'] - $res['total_tax'];
}

//echo "TOTAL".$res['total'];
return $res['total'];
}