Running Subtotal of Portal Records

[Kevinsky]

Hello,

I have an INVOICE table with a portal showing ITEMS sorted by ID, with a Field for the $ amount. It looks like this:

1 LineItem $25

2 LineItem $50

3 LineItem $10

I have a nice grand summary of $85 at the bottom of my invoice. But I would like a calculation to have a RunningSubtotal that shows in each of the LineItems, summarizing only up to the current ITEM portal record. It would look like this:

1 LineItem $25 $25

2 LineItem $50 $75

3 LineItem $10 $85

I've seen that using getNthRecord function, I can get a field value from a single other record (e.g. 3 records prior) but I can't figure out how to summarize a running subtotal for ALL records prior, while keeping the calculation focused only in the related set shown in the INVOICE portal.

Probably easy for a calculation expert, but I'm lost.

[comment]

Try defining a summary field in the LineItems table as a running total, and placing it in the portal.

[Kevinsky]

Bingo! Thanks.