How to apply discounts to existing invoices

Problem Description:

We have a set of hundreds of invoices that we want to apply a 10% discount to, as the customer is going into bankruptcy and is giving us the choice of accepting a commitment to accept 10% of the invoice amount.

Solution:

There is a "discount" item Type in QuickBooks, which is used to apply a discount to transactions. You can find it via QuickBooks UI -> Item List. We first create a 10% discount item in QuickBooks. There is a special item type "Discount," when you create the item. You can set the item account to the separate loss account.

When a discount item is created, please find it in the QODBC "Item" table and note down its ListID.
select * from Item

Find out the invoice you want to apply a discount to, in the QODBC "Invoice" table, and note down its TxnID.

Here is an example of adding one discount item (160000-934380927) to an existing invoice "EF0-1071503378" in our test company file:
INSERT INTO InvoiceLine (TxnID, InvoiceLineItemRefListID, InvoiceLineDesc) VALUES (‘EF0-1071503378', ‘160000-934380927, 'discount')

And this is the Discount Item in QuickBooks: