retain value

[paddyb]

Hi

I am trying to retain value of aval (where ablfl=y)in base_ for  same usubjid  ,I am getting missing values

wht can be issue?

proc sort data =  final3 out=final3_;
by usubjid avisit descending ablfl;
run;
data final4_;
set final3_;
by usubjid avisit descending ablfl;
retain aval_ base_;
if first.usubjid and ablfl='Y' then do;
aval_=aval;
end;
else aval_=aval_;


run;

[novinosrin]

if first.usubjid and ablfl='Y' then do;
aval_=aval;
end;
else aval=aval_;/*correction here i think*/