上传一个附件，是我样本的前四家公司的数据;

第一步之后，进行第二步：对每个公司，先把每个日期按顺序编上号，再重复抽样300次，可否用这个句子？！
data n.original1;
set n.original;
by co;
if first.co then n=0;
n+1;
run;
%macro BootMcr (b=1000);
Proc sql noprint;
  Select count(distinct co) into :ncos
from n.original1
order by co;
  Select distinct co, count(*) as count into :cos separated by' ' , :nobs separated by ' '
from n.original1
group by co;
quit;
data %do t=1 %to &ncos;
%let co= %scan(&cos, &t);  
boots&t (where=(co=&co)) %end;;
  Set n.original1;
Run;
Data n.bootstrap;
  Do sample=1 to &b;
   %do t=1 %to &ncos;
    %let nobs_= %scan(&nobs, &t);
      Do i=1 to 300;
         x=ceil(ranuni(&t)*&nobs_);
         Set boots&t point=x;
         Output;
       End;
     %End;
  end;
  Stop;
Run;
%MEND BootMcr;
%BootMcr;

you are right.