data test;
        input a b;
        datalines;
1    8
2    9
3   10
4    1
5    0
6    0
7    2
;
run;

data a(keep=a);
set test;
run;

data b(keep=b);
set test;
run;

proc sql;
        create table same as
        select * from a,b
        where  a.a=b.b;
quit;

data test;
        input a b;
        datalines;
1    8
2    9
3   10
4    1
5    0
6    0
7    2
;
run;

proc sql;
   create table wanted as
    select * from
           (select distinct a as newvar from test
         intersect
        select distinct b as newvar from test);
quit;

No need to create an additional dataset.

data test;
        input a b;
        datalines;
1    8
2    9
3   10
4    1
5    0
6    0
7    2
;

proc sql;
  select a.a as a, b.b as b
  from test a,
       test b
  where a.a=b.b
;
quit;

呵呵 多谢指教~

这个语句没用过，我要回去研究研究。谢谢了