ROW_NUMBER

ROW_NUMBER() OVER ([ query_partition_clause ] order_by_clause)

obclient> CREATE TABLE employees(LAST_NAME CHAR(10), SALARY DECIMAL, JOB_ID CHAR(32));
INSERT INTO employees VALUES('JIM', 2000, 'CLEANER');
INSERT INTO employees VALUES('MIKE', 12000, 'ENGINEERING');
INSERT INTO employees VALUES('LILY', 13000, 'ENGINEERING');
INSERT INTO employees VALUES('TOM', 11000, 'ENGINEERING');
COMMIT;
Query OK, 1 row affected (0.00 sec)

obclient> SELECT LAST_NAME, ROW_NUMBER() OVER(PARTITION BY JOB_ID ORDER BY SALARY) NTL FROM employees;
+-----------+------+
 LAST_NAME  NTL  
+-----------+------+
 JIM           1 
 TOM           1 
 MIKE          2 
 LILY          3 
+-----------+------+
4 rows in set (0.00 sec)