The "SalesTxn Document Actual Discount Amount" is what was actually discounted on the invoice. Remember that it is a document field, so it is repeated for each line on the invoice. Use PowerPivot to grab the unique value for each invoice.
To get the discount on an invoice by invoice basis use the patented feature in the QQube General Ledger Detail analytic where linked transactions are grouped in consecutive rows. The master link # is actually the QB Transaction number. You will see this in the QQube Configuration Tool examples.
Further, in QQube 7.1 (Released 2/21/2019) we broke out all of the different types of discounts that can occur in QuickBooks transactions. For example:
See this announcement on QQube 7.1: https://clearify.com/articles/product/4475/qqube-7-1-build-471-details
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