data test;
   do age=1 to 100;
      output;
   end;
run;

proc sql noprint;
   select age into : ages separated by ',' from test;
   create table test1 as
   select * from test
   where age eq (
               select distinct pctl2(90,&ages) as p90
               from test
   );
quit;

多谢大神！这几天出差没法上网回复晚了，抱歉，谢谢你的回答！