I have a column of dates, a column of customers and a column of sales totals.
If I have a few rows of data it would look like this.

01-01-07 john smith builders $200.00
10-10-07 john smith buiders $800.00
01-15-07 Blarney Builders $600.00
02-10-07 John Smith Buiders $500.00
02-11-07 Blarney Builders $450.00
01-15-07 Blarney Buiders $800.00

I need a formula that will recognize what month the sale was made in and
give me a total by customer for each month. Does that make sense?