i have the following case:

DATE Ammount
01.12.06 50
05.12.06 100
12.12.06 200
25.12.06 240
01.01.07 200
15.01.07 210
27.01.07 111
etc...


I would like to SUM the ammounts by month

month ammount
dec. 06 590
jan. 07 521

how do I do that?

thanks!