MERGE Statment

Use the MERGE statement to select rows from one or more sources for conditionally update or insertion into a table or view. 

CREATE TABLE bonuses (employee_id NUMBER, bonus NUMBER DEFAULT 100);

INSERT INTO bonuses(employee_id)
   (SELECT e.employee_id FROM employees e, orders o
   WHERE e.employee_id = o.sales_rep_id
   GROUP BY e.employee_id); 

SELECT * FROM bonuses;

EMPLOYEE_ID      BONUS
----------- ----------
        153        100
        154        100
        155        100
        156        100
        158        100
        159        100
        160        100
        161        100
        163        100

MERGE INTO bonuses D
   USING (SELECT employee_id, salary, department_id FROM employees
   WHERE department_id = 80) S
   ON (D.employee_id = S.employee_id)
   WHEN MATCHED THEN UPDATE SET D.bonus = D.bonus + S.salary*.01
     DELETE WHERE (S.salary > 8000)
   WHEN NOT MATCHED THEN INSERT (D.employee_id, D.bonus)
     VALUES (S.employee_id, S.salary*0.1)
     WHERE (S.salary <= 8000);

EMPLOYEE_ID      BONUS
----------- ----------
        153        180
        154        175
        155        170
        159        180
        160        175
        161        170
        179        620
        173        610
        165        680
        166        640
        164        720
        172        730
        167        620
        171        740