Excel formula for "select sum(B) where month(A)=3"

Solution 1:

As column A is a date you will need something like this to test that the month is March(3), April(4) etc to match it, below is one way

ie for March

=SUMPRODUCT(--(MONTH($A$1:$A$50)=3),$B$1:$B$50)

for April
=SUMPRODUCT(--(MONTH($A$1:$A$50)=4),$B$1:$B$50)

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I would first create an intermediary column containing the dates (=Month(a1) and copy down column B.

Then use the following:

=SumIf(b1:b1101,"=4",c1:c1101)

This assumes that the B column is where the month is held, and that the month is equal to 4.