I currently use the following formula to track employee earnings.

=SUMPRODUCT(('2004-JAN_05'!$C$2:$C$20000=$A43)*('2004-JAN_05'!$J$2:$J$200000)*'2004-JAN_05'!$J$2:$J$20000)

Where
Column C represents the emplyee
Column J represents the earnings

I need to add another condition that adds the month to the criteria ( that
would be in cloumn B). Note cloumn B contains days for any given month so I
need to total all earnings by employee by month.

Thanks