Excel SUMIF between dates

Question

I have column A with date values formatted as mm/dd/yyyy. I am trying to sum the values of column B if A >=DATE(2012,1,1) AND

=SUM(B:B) sums

Answer 1

this works, and can be adapted for weeks or anyother frequency i.e. weekly, quarterly etc...

=SUMIFS(B12:B11652,A12:A11652,">="&DATE(YEAR(C12),MONTH(C12),1),A12:A11652,"<"&DATE(YEAR(C12),MONTH(C12)+1,1))