Retaining first value across multiple rows

Question

Hello,

Simple question. How do I keep the first score (AVALXC) once in the first row and the rest of the crows column blank per PATID?. so PATID 10017 would have a score of 12 for row 1 but wouldn't repeat and then the same for 100022 etc.This is what I tried.

proc sql;
    create table distinctSSI as
        select distinct SUBJID
                        ,AVALXC
                        
        from adtte
        where AVALXC is not null
    order by 1;
quit;
proc sort data=adtte; by SUBJID;
data FINALa;
    merge adtte (drop=AVALXC)
          distinctSSI;
    by SUBJID;
    RUN;