Sorry, not enough letters in title.

Should read "Running Total, evaluate on formula and reset on change of Group."

I've googled around a bit and can't seem to find a solid answer. I have two groups, we'll say 'Register' and 'Date'. In the details band, because of the way this view is setup, the details band will repeat. I have no control over software or the database and I don't believe it could be fixed if I did. This being said, I need some running totals going which I've mostly sorted out.
What's happening is that in order to get around the repeated numbers which I need to only sum unique values I have created a running total for let's say FOOD.
So I made FOOD_TOTAL which sums. The evaluation is a formula namely:

NOT({dbo.sales.foodtotal}=Previous({dbo.sales.foodtotal}))

Then I'm resetting on change of group 'Date'

Anyway that's my logic on this. OK well it kinda works. The problem is, and what I can't wrap my skull around is why all of the groups except the first one displays the running total correctly (blank). I can kinda understand except the same formula/total works if there's not two groups. So I'm thinking Crystal somehow is confusing itself if because of the multiple groups.

So for giggles, I change the above formula to:

{dbo.sales.foodtotal}<>NEXT({dbo.sales.foodtotal})

This produced the exact opposite results. All groups display the running total except the last group now. So depending on which of the formula I use, I lose the last or first running total.

So I get it, the evaluation breaks on two groups depending on the evaluation 'direction'. But certainly CRXI should understand that because I'm explicitly asking to reset on group and only eliminating details from the total that I would want the first or last group included in the total.

Am I missing something?

Thanks.

hmm...well OK srsly Crystal? I'm baffled neither of the formulas up top would work, but a combination of the two does?

NOT({dbo.sales.foodtotal}=Previous({dbo.sales.foodtotal})) OR {dbo.sales.foodtotal}<>NEXT({dbo.sales.foodtotal})

I'm not even sure I want to know why it works

anyway I hope this saves someone some time when Rtotaling on duplicate details.

It has to do with how crystal handles nulls.
Using previous and next can ignore the first or last row in the data set because the previous or next value is null. If you do not tell crystal how to handle the null it won't evaluate the formula at all.
You likely could also use your original formula the pick list option of 'default vales for nulls' and it would rectify the issue.