Combination of Filters and SUM

I’m currently adding our product demand (think line items) and available inventory into 2 different tables. I’d like to fire off an email or create some kind of alert if the demand of any product is greater than the available product quantity. I thought this would be easy, but now I’m realizing rollups can’t really be filtered. Does anyone have any ideas on how to tackle this?

Need some more clarification.

But this is what I have done in lieu of no filters on rollups. Example, say I have a Table “Payments” with a Payment Amount field, I can also cancel the payment and there are different types of payment types e.g. Check and Cash. Generally you would probably add a Status field and set the status has “Cancelled” and the Payment Type field set as Check or Cash. But you there is no possibility of filtering on the Status field.

My solution is to add a the following fields along with the Payment Amount, these are Cash Payment Amount, Check Payment Amount and a Cancel Amount field.

And then rollup on these fields. But what if you wanted to know the Cancelled Cash Amount and the Cancelled Check Amount then I would add fields representing these also, since the Cancel Amount only gives the total of Cancelled payments.

I hope this was clear enough. You can probably use a similar pattern as a work around for your use case.