Omit certain values from sum calculation based on a checkbox?

[mrswombat]

I have a portal that shows me the packing slips of a job and it includes the fields "billed checkbox" and "quantity shipped" fields. I frequently partial bill these jobs, so some of the packing slip records have the "billed checkbox" checked from previous partial bills.

I would like a "partial bill qty" field on my invoice to auto enter only the sum of "quantity shipped" if the "billed checkbox" is unchecked. So far, I've only managed to come up with calculations that keep summing up all the fields and I can't figure out a way to omit the values in the "quantity shipped" fields if the "billed checkbox" is checked. Any ideas?

[eos]

Easiest solution would be to create a calculation field in the PackingSlips table that is defined as “quantity shipped if not billed" and sum up this field in Jobs.

[Vaughan]

You need another calc field in the invoice line items records that only shows the quantity shipped if the billed checkbox ic unchecked:

Quaitity_Unbilled = Case( isempty( billed ) ; Quantity )

In the invoice table, make a total field that Sums() the unbilled calculation.

[mrswombat]

Wow, thank you as always for your help Vaughan. Once again, worked beautifully!