Problem

I need to update the old terms of a customer in QuickBooks. They used to be due upon receipt, and we need to move them to net 30. I need to go back and change all the old due dates to reflect the new terms. How can I update the DueDate to remember what I try to do? I have tried the following:

UPDATE Invoice SET DueDate = DateAdd("d", 30, TxnDate) WHERE CustomerRefListID = '80000005-XXXXXXXXX'

UPDATE Invoice SET DueDate = {fn TIMESTAMPADD(SQL_TSI_DAY, 30, DueDate)} WHERE CustomerRefListID = '80000005-XXXXXXXXX'

I found this, but I am still getting an error "Invalid operand for operator <assignment>

Solution 

Please try this query in QODBC Support Wizard to see if it can get your jobs done:

UPDATE Invoice SET DueDate = {fn CONVERT( {fn TIMESTAMPADD(SQL_TSI_DAY,30, DueDate )}, SQL_DATE)} WHERE CustomerRefListID = '80000005-XXXXXXXXX'

And if you are going to do this in MS Access linked table, please create a query and use SQL Statement like this:

UPDATE Invoice SET DueDate = DateAdd("d", 30, TxnDate) WHERE CustomerRefListID = '80000005-XXXXXXXXX'