Hi. You can try this solution. Maybe not the most sophisticated but it should work. data TestData; infile datalines dlm=' '; input Var1 date date9. ; format date date9.; datalines; 2312544 12-Oct-14 2312544 21-Oct-14 2312544 19-Nov-14 2312544 11-Dec-14 2312544 28-Dec-14 2312544 9-Jan-15 2312544 10-Jan-15 2312544 11-Jan-15 2616131 10-Aug-08 2616131 7-Dec-08 2616131 16-Dec-12 2616131 12-Apr-13 2616131 24-Jul-13 2616131 28-Sep-14 2616131 3-Nov-14 2616131 9-Mar-15 24526667 28-Jun-15 84895398 29-Mar-15 5555666 16-Dec-12 5555666 12-Apr-13 5555666 30-Jul-13 5555666 28-Sep-14 5555666 30-Sep-14 5555666 15-Oct-14 ; data testdata; set testdata; if date in('28SEP2014'd, '28DEC2014'd, '29MAR2015'd, '28JUN2015'd) then flag=1; run; Proc Sort Data=testdata Out= test_sorted; By var1 date ; Run; data Want; set test_sorted; by var1; if first.var1 and last.var1 then delete; * singel observations; lag_date=lag(date); if flag then days=date-lag_date; if flag; drop flag; run;
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