how to get worst grades by using by variable

[noda6003]

I have a dataset which has grades and variable named chk. what i want it from is to get grades which are more than the one initially i.e chk gt 0

DATA work.check;
    LENGTH
        ID                 8
        grade              8
        chk                8 ;
    FORMAT
        ID               BEST12.
        grade            BEST12.
        chk              BEST12. ;
    INFORMAT
        ID               BEST12.
        grade            BEST12.
        chk              BEST12. ;
    INFILE DATALINES4
        DLM='7F'x
        MISSOVER
        DSD ;
    INPUT
        ID               : BEST32.
        grade            : BEST32.
        chk              : BEST32. ;
DATALINES4;
110
110
121
220
221
211
211
320
310
331
;;;;

something like this since ID 1 has more grade than it has in chk=0 and ID=3 has grade=3 which is more than in chk=0.

ID	grade	chk
1	2	1
3	3	1

Not sure how to do it programmatically. Any help

[Kurt_Bremser]

Something like this:

proc sql;
create table want as
  select *
  from check
  where chk = 1
  group by id
  having grade = max(grade)
;
quit;

?