data test1;
input stkcd $ year asset eps;
cards;
000001 1998 123 0.5
000001 1999 234 0.7
000002 1998 123 0.5
000002 1999 234 0.7
;
run;

data test2;
input stkcd $ f2 feps_mean;
cards;
000001 1999 0.6
000001 2000 0.8
000002 1999 0.1
000002 2000 0.2
;
run;

proc sql;
create table test as
select coalesce(test1.stkcd,test2.stkcd) label='stkcd', f2, eps, eps-feps_mean as difference from test1 inner join test2
on test1.stkcd=test2.stkcd and year=f2;
quit;

接楼上的数据，使用merge练一下
proc sort data=test1
        by stkcd year;
run;
proc sort data=test2
        by stkcd f2;
run;

data test;
        merge test1(in=t1) test2(rename=(f2=year) in=t2);
        by stkcd year;
        if t1 and t2 ;
        diff=feps_mean-eps;
run;
proc print;
run;

用merge的时候要排序 与rename；用sql 直接join year=f2

谢谢

谢谢你的解答