SQL> SELECT deptno, ename,
2 ROW_NUMBER () OVER (PARTITION BY deptno ORDER BY sal DESC) seq
3 FROM emp;

DEPTNO ENAME SEQ
---------- ---------- ----------
10 KING 1
10 CLARK 2
10 MILLER 3
20 SCOTT 1
20 FORD 2
20 JONES 3
20 ADAMS 4
20 SMITH 5
30 BLAKE 1
30 ALLEN 2
30 TURNER 3
30 WARD 4
30 MARTIN 5
30 JAMES 6

14 rows selected.

SQL> select deptno,
2 max(decode(seq,1,ename,null)) highest,
3 max(decode(seq,2,ename,null)) second,
4 max(decode(seq,3,ename,null)) third
5 from (
6 select deptno,ename,
7 row_number() over
8 (partition by deptno order by sal desc) seq
9 from emp)
10 where seq <=3 group by deptno
11 /

DEPTNO HIGHEST SECOND THIRD
---------- ---------- ---------- ----------
10 KING CLARK MILLER
20 SCOTT FORD JONES
30 BLAKE ALLEN TURNER