Dear all, I have a longitudinal dataset in which each patient is recorded with multiple dates. Each date is counted as a separate row. Note that a patient could have multiple entries for the same date. The data layout is as follow: ID Date Var1 Var2 1 2002 4 5 1 2002 5 7 1 2003 7 9 2 2001 4 8 2 2002 3 8 Ideally, I would like to delete observations from the first recored date for each patient, so the output data would look like: ID Date Var1 Var2 1 2003 7 9 2 2002 3 8 I have tried proc sort with nodupkey as well as proc sql distinct but none of them gave me the output i want. I was also trying to come up with an indicator to code for the first date within each patient but did not succeed. I'd really appreciate if anyone could help!
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