yogi_Compute Sum Of Amount Spent For A Specified Category In A Specified Month

Yogi Anand, D.Eng, P.E.       Google Spreadsheet    Post  #632   Jul 16, 2012     www.energyefficientbuild.com.


user tranqui said:(http://productforums.google.com/forum/#!category-topic/docs/spreadsheets/b-rfaB1Yedw)
Formula Error #NUM! 

I have been using this for month in a speadsheet. Recently it is giving me an Error #NUM! Argument is blank. I don't understand why this has stopped working.

=ArrayFormula(SUMPRODUCT(INDEX(($D$5:$D$901))*(($F$5:$F$901=H8)*(MONTH($B$5:$B$400)=1))))

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there has recently been a change in how Google spreadsheet handles date and time related elements for blank cells -- use of IFERROR function should take care of the problem in your case. You also have a redundant INDEX function call in your formula.

I have also generalized the solution for looking at the SUM by a specified month