Hi, I have a data set that contains Patient IDs, Drugs, and date of the prescription fill. I am trying to identify the number of individual patients that were on a drug in a given year. A patients typically have multiple records within a year, as each record representation a prescription fill date. The data structure looks like this: Patid DrugName Year 100 Drug 1 2013 200 Drug 1 2013 200 Drug 1 2013 200 Drug 1 2013 200 Drug 1 2013 300 Drug 1 2013 100 Drug 1 2014 300 Drug 2 2013 100 Drug 2 2015 400 Drug 2 2015 400 Drug 2 2015 400 Drug 2 2015 300 Drug 3 2014 300 Drug 3 2015 100 Drug 3 2015 In my head, the output should should look something like this: Drug year #Patients Drug 1 2013 3 Drug 1 2014 1 Drug 2 2013 1 Drug 2 2015 1 Drug 3 2014 1 Drug 3 2015 2 I have tried proc summary, but that just gives me a frequency of the number of records, by drug & year. I am thinking proc sql using count/distinct would work, but not sure how to group by drugname & year, as I am not very good at this... Any assistance is greatly appreciated. Thanks! Chris
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