Live ORACLE

DROP TABLE employees_temp CASCADE CONSTRAINTS PURGE;

CREATE TABLE employees_temp
AS
SELECT *
FROM   employees;



DECLARE

CURSOR c1 IS

SELECT employee_id,

       salary

FROM   employees_temp

WHERE  salary > 2000

       AND ROWNUM <= 10; -- 10 arbitrary rows

CURSOR c2 IS

 SELECT *

 FROM   (SELECT   employee_id,

                  salary

         FROM     employees_temp

         WHERE    salary > 2000

         ORDER BY salary DESC)

 WHERE  ROWNUM < 5; -- first 5 rows, in sorted order



BEGIN

-- Each row gets assigned a different number

UPDATE employees_temp

SET    employee_id = ROWNUM;

END;

/

Using ROWNUM