Help with SUMPRODUCT & converting date to value

[jrproudfoot]

I have the following Excel calculation, shown below. It is searching cells
A6:A1000 on various sheets for data which fall between a certain date/period
range, and is then adding the values in cells L6:L1000 together to display on
the summary.

The problem I have is that the data in ranges L6:L1000 are supposed to be
Dates, but the only way i can return a value without an error is to use a
number (e.g. of 1) instead. How can I use Dates within cells L6:L1000, and
still return the same totals?

Many thanks in advance for any tips you can offer!

=SUMPRODUCT((Office!L6:L1000)*(Office!A6:A1000>=40269)*(Office!A6:A1000<=40299)+((Commercial!L6:L1000)*(Commercial!A6:A1000>=40269)*(Commercial!A6:A1000<=40299)+((Hospitality!L6:L1000)*(Hospitality!A6:A1000>=40269)*(Hospitality!A6:A1000<=40299))))

 

[Bob Phillips]

Do you mean like this

=SUMPRODUCT((ISNUMBER(Office!L6:L1000))*(Office!A6:A1000>=--"2010-04-01")*(Office!A6:A1000<--"2010-05-01")
+((ISNUMBER(Commercial!L6:L1000))*(Commercial!A6:A1000>=--"2010-04-01")*(Commercial!A6:A1000<--"2010-05-01")
+((ISNUMBER(Hospitality!L6:L1000))*(Hospitality!A6:A1000>=--"2010-04-01")*(Hospitality!A6:A1000<--"2010-05-01"))))