Are you mixing macro code and data step variables? Because when i run: %let year1 = %sysfunc(year("13JUL2013"d)); It works .. Log: 424  %let year1 = %sysfunc(year("13JUL2013"d)); 425  %put Year One=&year1; Year One=2013 If you want to create a macro variable from a field in your data step, you need to use call symput(), not %let. data _null_;   dt = date();   put dt=date9.;   call symput('YearOne',year(dt)); run; %put Year One=&yearOne; ... View more

I would second @MichaelPearce, and using lag() to make it even less verbose: data want;   set have (drop=entry);   by id; Entry=ifn(first.id,0,lag(exit)); run; Haikuo ... View more