orclz> select deptno,rownum join_col from (select deptno from test order by deptno desc) ;

    DEPTNO   JOIN_COL
---------- ----------
        30          1
        20          2
        10          3

orclz> select ename,rownum join_col from (select ename from test order by ename) ;

ENAM   JOIN_COL
---- ----------
A             1
B             2
C             3

orclz>

SQL> select t.*,
  2         row_number() over (order by ename) ename_rk,
  3         row_number() over (order by deptno desc) detp_rk
  4  from test t
  5  /
ENAM     DEPTNO   ENAME_RK    DETP_RK
---- ---------- ---------- ----------
C            30          3          1
B            20          2          2
A            10          1          3

3 rows selected.