Here is one way. A format to create groups by week within client and count, then count the result. proc format library=work; picture yearweek (default=8) other= '%Y/%0U' (datatype=date); run; proc freq data=have noprint; tables client * date /list norow nocol nopercent out=temp; format date yearweek. ; run; The set TEMP will have one record per client per week. You haven't provide an example of what the final output(s) might look like but you can get a total of clients per week by summarizing the Temp dataset variable date. A count of client would give you the total unique clients in the data. proc freq data=temp; tables date; run;
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