SAS程序员测试（二） Try this one.

shiyiming

proc sort data=tem;
  by vol id date;
  run;

data test(drop=date);
  set tem;
  by vol id;
if first.id=1 then do;
    Bdate=date;
    retain id bdate vol;
    end;
if last.id then do;
   Edate=date;
   output;
   end;
format bdate edate yymmdd10.;
run;

proc sort data=test;
by id vol;
run;