EMP_NAME	EMP_INV

Pras	CTI
Pras	CTI
Shariq	Witness
Kate	CTI
Shariq	Assisted
Shariq	Witness

CREATE TABLE EMP_INV
(
  EMP_NAME  VARCHAR2(100 BYTE),
  EMP_INV   VARCHAR2(100 BYTE)
)

Insert into EMP_INV
   (EMP_NAME, EMP_INV)
 Values
   ('Shariq', 'Witness');
Insert into EMP_INV
   (EMP_NAME, EMP_INV)
 Values
   ('Shariq', 'Assisted');
Insert into EMP_INV
   (EMP_NAME, EMP_INV)
 Values
   ('Kate', 'CTI');
Insert into EMP_INV
   (EMP_NAME, EMP_INV)
 Values
   ('Shariq', 'Witness');
Insert into EMP_INV
   (EMP_NAME, EMP_INV)
 Values
   ('Pras', 'CTI');
Insert into EMP_INV
   (EMP_NAME, EMP_INV)
 Values
   ('Pras', 'CTI');
COMMIT;

SELECT emp_name, emp_inv, RANK () OVER (ORDER BY emp_name, emp_inv)
  FROM EMP_INV

SQL> select
  2    dense_rank() over (order by emp_name, emp_inv) rb,
  3    emp_name,
  4    emp_inv
  5  from emp_inv
  6  order by emp_name, emp_inv;

        RB EMP_NAME   EMP_INV
---------- ---------- --------------------
         1 Kate       CTI
         2 Pras       CTI
         2 Pras       CTI
         3 Shariq     Assisted
         4 Shariq     Witness
         4 Shariq     Witness

6 rows selected.

SQL>

SELECT emp_name, emp_inv, RANK () OVER (ORDER BY emp_name, emp_inv)
  FROM EMP_INV