Alright. Create a new variable called Var InvoiceNo Sum of Qty defined as follows…
=Sum([Qty]) In ([InvoiceNo])
The key with this formula is that it will give you the total for each InvoiceNo on all rows. I know this isn’t what you want, but I want to show the steps to get there.
Now add breaks on InvoiceNo and the new Var InvoiceNo Sum of Qty variable.
Next right-click on the table and choose “Breaks > Manage Breaks…”. We do not want break headers or footers for either break. For InvoiceNo we want to choose “Display all” under Duplicate values and for Var InvoiceNo Sum of Qty we want to choose “Display first”. They should look like this…
Finally in the Format Table properties check the “Table headers” checkbox. It got unchecked behind the scenes when the breaks were added.
And there you have it.