Running Balance

[KADL]

I've read lots of postings, but my problem has a twist. Briefly, I have a
sales, inventory and weekly production planning situation. The table already
has the sales figures for the whole week. My report has a grouped sales
amount for each day (multiple customers ordering the same item) and I did
this in a query. I need to know how much of each item must be produced each
day.

The basic concept is [Inv] - [Par] - [Sales] = [AmtToMake].
[AmtToMake] is changed to zero if it is positive. (Note: Par is how much has
to stay in inventory).

I start with [Inv] - [Par] = [BeginBal] for the week.
Then for each day, [Sales] - [BeginBal] = [AmtToMake]

The problem is the value of [Begin Bal] needs to be reduced in the
calculation for each subsequent day by the amount of total sales for that day.

Example:
Day Item Inv Par (BeginBal) Sales AmtToMake
Mon X 20 5 15 10 0
Tue X 5 12 7

What should be done in the query/queries and what belongs in the report?

I hope this makes sense. Please help!

Thanks!