to mofengchenxi: 不是什么时候都适合用大杀器的.
最简单的方法:分两步来做:
1) 1993~1999;
2) 2000~2005;
[code:2egukg26]
proc sort data=s1; by id industry;
proc sort data=s2; by industry;
proc sort data=s3; by industry;
data d1;
merge s1(where=(year<=1999)) s2;
by industry;
run;
data d2;
merge s1(where=(year>=1999)) s3;
by industry;
run;
data out;
set d1 d2;
run;
[/code:2egukg26]