https://communities.sas.com/t5/SAS-Procedures/processing-data-set/m-p/42574#M11075 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! Wed, 30 Jun 2010 18:48:58 GMT deleted_user 2010-06-30T18:48:58Z https://communities.sas.com/t5/SAS-Procedures/processing-data-set/m-p/42574#M11075 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! Wed, 30 Jun 2010 18:48:58 GMT https://communities.sas.com/t5/SAS-Procedures/processing-data-set/m-p/42574#M11075 deleted_user 2010-06-30T18:48:58Z https://communities.sas.com/t5/SAS-Procedures/processing-data-set/m-p/42575#M11076 I think that this thread talks about just the question you are asking:<BR /> <BR /> <A href="http://support.sas.com/forums/thread.jspa?threadID=10257&amp;tstart=0" target="_blank">http://support.sas.com/forums/thread.jspa?threadID=10257&amp;tstart=0</A> Wed, 30 Jun 2010 19:47:43 GMT https://communities.sas.com/t5/SAS-Procedures/processing-data-set/m-p/42575#M11076 Doc_Duke 2010-06-30T19:47:43Z