DATA ALL ; SET ALL ; by pa_id sa_id admin notsorted; IF first.admin then seq +1; run; Dear all,   I need your unreserved help. I am using SAS version 9.4.  I want to count admin variable in cumulative fashion for value "o" by pa_id, sa_id, time.  the structure of the data is given below     I am expecting like this    ... View more

   Hi,     I am working on the prescription dataset from a health organization.  the dataset contains the following variables in the snapshot below.  I want to count a number prescription per patient based on the following criteria,  If the deliv_date2 is less than seven and the same ATC code for the individual patient then set a number of prescription is equal to one and sum DDD otherwise count the number of prescription. Thank you in advance!!   data thesis.presc2; set thesis.presc; by patient; if first.patient then lastdate=.; else lastdate = lag(deliv_date2); datediff = deliv_date2-lastdate; run; proc sql; CREATE table thesis.presc3 as select patient,  reimburs_cat, source,  atc, AdminRoute, N_presc, count(N_presc) as Co_Pres, Center, deliv_date2, DDD,datediff From thesis.presc2 where datediff >= 7 group by patient ; quit;         ... View more