06-14-2012 04:55 AM
Just do a proc freq and merge the output table back on to the original. I've used the coalesce function in the remerge query to put a 0 for any months where the codes 5523,1213 don't appear.
proc freq data=have (where=(codes in (5523,1213)) noprint;
table monthyear / out=want;
create table have as select
coalesce(b.count,0) as distcd
from have as a left join want as b on a.monthyear=b.monthyear;