I have a sales order spreadsheet that gets updated daily from our ERP system.
The worksheet has the following columns:
1. Customer code (each customer could have several entries per month)
2. Order date (the current worksheet has two years of history in addition to
the daily updates)
3. Amount

What I would like to do is make a new worksheet that has the following
columns:
1. Customer code listed once for each customer
2. Total sales summed by month ( so I would have a column for each 2 years
of history and will add each new month)

I know I could do this with a pivot table but for internal company reasons I
would like to know if anyone can tell me how to do it with a formula.

Thanks in advanced for your help!!!
Charles