How to: Calculate purchase order Subtotal Amount

Today, Celeb Kiran has asked me on my post How to: Calculate purchase order total value how get the Subtotal Amount instead of Total Amount.
Since one man’s doubt is another man’s doubt I have decided to post how to get the PO Subtotal amount modifying the previous code and adding some comments.

This value can also be found on Totals form, which can be accessed through:
Accounts payable/Common/Purchase orders/All purchase orders/Tab – Purchase Order/Group – View/Totals

Today I will use the PO BRMF-000018. The difference between Subtotal and total amount makes it a perfect example.

As always, I will use a job as example:

static void _GetPurchTotals(Args _args)
{
    PurchTotals purchTotals;
    PurchTable  purchTable  = PurchTable::find('BRMF-000018'); //Purchase order Number

    AmountCur  totalAmount;
    AmountCur  subTotalAmount;
    ;

    // Initializing PurhTotals using the PO BRMF-000018 as parameter
    purchTotals = PurchTotals::newPurchTable(purchTable);
    // Calculating values
    purchTotals.calc();

    // Total Amount
    totalAmount     = purchTotals.purchTotalAmount();
    // SubTotal Amount
    subTotalAmount  = purchTotals.purchBalance();

    // Displaying Results
    setPrefix('Purchase Order');
    setPrefix(purchTable.PurchId);
    info(strFmt('Subtotal amount: %1', subTotalAmount));
    info(strFmt('Total amount: %1', totalAmount));
}

Executing the code, the infolog shows the following results: