Summarize grouping by year and month

Question

I have a worksheet Movements with two fields:

mydate      | amount
2009-01-01  | 10.00
2009-01-02  | 13.00
2009-02-01  | 11.00
2009-02-05  | 12.00
2         


        

Answer 1

You can do it with an array formula, i put the formula in A2 and in A1, i put the month number:

=ARRAYFORMULA(SUMPRODUCT(1*(MONTH(Sheet1!$A$2:$A$6)=A1)*Sheet1!$B$2:$B$6))

See the doc in action in Google Spreadsheet

[EDIT] If you want both year and month:

=ARRAYFORMULA(SUMPRODUCT(1*(YEAR(Sheet1!$A$2:$A$8)=A2)*(MONTH(Sheet1!$A$2:$A$8)=B2)*Sheet1!$B$2:$B$8))