data new;
   input a $ b c;
   datalines;
1 4 6
1 2 3
2 3 4
2 3 5
;
run;

/* This creates a macro variable for every  */
/* value of A as well as a counter variable */
data _null_;
   retain count 0;
   set new;
   by a;
   if first.a then do;
      count+1;
      call symput('val'||left(count),trim(left(a)));
   end;
   call symput('last',left(count));
run;

options mprint;
%macro test;
/* This %DO loop performs one PROC PRINT  */
/* for every value of A                   */
   %do i = 1 %to &last;
      proc print data=new;
         where a="&&val&i"; /* no quotes used if A is numeric */
         title "This is the value of A: &&val&i";
      run;
    %end;
    %mend test;

/* This step calls the macro  */
%test