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

Joe - your answer did not work for whatever reason, but got me on the right track to figure it out. Thank you!

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