Automatically change the result

[randomwalker]

Hi,

From cell A1 to A30, I input dates from 2011-1-1 to 2011-1-30; From cell B1 to B30, I input numbers, such as 55, 37, .... totally, there are 30 numbers.

In cell C1, I input 2011-1-1, in cell C2, I input 2011-1-12. In cell C3, I want to have a formula to sum up the number from cell b1 to b12. How to write that formula so that the result in C3 change automatically if I change the date in cell c2?

Hopefully, I have made myself clearly enough.

Thanks for help!!!

 

[rs2k]

Try this;

=SUMPRODUCT(($A$1:$A$31 >= C1)*($A$1:$A$31 <= C2)*($B$1:$B$31))

I have used 31 days, but adjust to suit.

HTH
Colin