Still need help on annualized rolling sum

[Guest]

I am trying to calculate an annualized rolling sum for data as follows:

ColumA Column B
10/01/97 5
10/12/97 6
12/5/97 3
1/5/98 2
1/15/98 6
6/15/98 9
8/12/98 7
etc

I want to be able to calculate on each date the sum of column B for the past
year.

 

[Guest]

Assume your data goes from row 1 to 30, place this formula in C1 and drag down.

=SUMPRODUCT(--($A$1:$A$30<A1),--($A$1:$A$30>=A1-365),$B$1:$B$30)