Try this:

Use cells to hold the date boundaries.

E1 = start date
F1 = end date

=SUMPRODUCT(--(A1:A10=E1),--(A1:A10<=F1),--(B1:B10<""),C1:C10)

--
Biff
Microsoft Excel MVP


"joe@malvern" wrote in message
...
date cost $ sales $
01/21/09 $4.00 $8.00
01/21/09 $7.00
02/21/09 $5.00 $8.00
02/28/09 $3.00

what formula can I use to look at the "date" column, select a time period
(i.e 01/01/09-01/31/09) and sum the the corresponding "Sales $" only if
the
"cost $" is <"" ?

thanks