processing data set

[deleted_user]

Relatively new to SAS and am struggling with a simple concept. I have a dataset with series of monthly sales figures and I just want to add a column that shows the sales for the last 12 months (I need to sum the last 12 months of the monthly column). I'm guessing there is a relatively simple way to do this, but have not been able to get anything to work. Any advice? Thanks in advance!

[Doc_Duke]

I think that this thread talks about just the question you are asking:

http://support.sas.com/forums/thread.jspa?threadID=10257&tstart=0