Partitioned Running Totals in SAS

Question

How can I create a new column for an existing dataset that is the running total of an existing column - partitioned by some identifier?

ID |  Value |     New Val         


        

Answer 1

In the data step this is accomplished with the sum statement.

data want;
  set have;
  by id;
  if first.id then running_total=0;
  running_Total + value;
run;

In PROC SQL this would be impossible unless you have an ordering variable (in which you could do something like this):

proc sql;
  create table want as
   select id, value,
     (select sum(value) from have V
     where V.id=H.id and V.ordervar le H.ordervar
     ) as running_total
   from have H
 ;
quit;

But SAS doesn't have a partition by concept - the SAS data step is far more powerful than that.