PROC SQL; CREATE TABLE ta1 AS SELECT DISTINCT id, icd, feq, date group by id , date,icd, order by id, date, icd; QUIT; Now if I want to remove some records if there are two records on same day, what should I do I can not simply drop freq=2, because I do want to keep those have two visits on different days with same icd code     ... View more

I want to merge two datasets. I previously needed to sort them first, them data want set have1 have2 indsname=ind contributing_tbl=ind; run;   In this way, I get a new variable indicating where it is originally from   However, use "set" is too slow and needs to sort first, which takes more time, I want to change to use proc sql; however, I need advice from you how to have a simiar statement that adds a column that indicting where it is orginally from have1, or have2, would you please advice? Thanks. ... View more

proc sort data=have nodupkey; by id date; run; data want; set have; by id date; if first.id then index=1; else index=2; run; proc freq data=want; tables cat1*cat2; where index=1; run; I prevoiusly used index=2 to mark if those obs have multiple records (visits). But this has limitation, only the later visits are counted. This time I need to mark, if the patient has mulitple visit (might see doctors same day many times), whether it is the first visit, or the later visit, I want to create a variable that the patient has "multiple visit"   That means, if index=2, all the patient's records will mark as "multipe visit" Any idea how to do? Thanks. ... View more