ouhaicourse
如何用宏程序实现循环
proc sql;
create view wxq1638 as select *,normal(0) as w from return_2
order by calculated w;
data a3;set wxq1638 (obs=2);/*每层随机抽取两个观测*/
if num1^=num1 then delete;
run;
proc sql;
create table selectstock as
select num1,date,p,index,return
from return_2
where num1 in select num1
from a3
where return_2.num1=a3.num1;
run;
