Função Oracle DECODE

SELECT * FROM hr.employees;

SELECT first_name,
       salary,
       DECODE (job_id,'IT_PROG', salary * 1.2,
                      salary * 1.1) AS aumento_salarial
  FROM hr.employees;

SELECT first_name,
       salary,
       DECODE (job_id,'IT_PROG', salary * 1.2,
                      salary * 1.1) AS aumento_salarial
  FROM hr.employees
 WHERE employee_id = 100
    OR job_id = 'IT_PROG';

SELECT first_name,
       salary,
       DECODE (job_id,'IT_PROG', salary * 1.2,
                      'AD_PRES', salary * 1.3) AS aumento_salarial
  FROM hr.employees
 WHERE employee_id = 100
    OR job_id IN ('IT_PROG', 'AD_VP');

SELECT first_name,
       salary,
       DECODE (job_id,'IT_PROG', salary * 1.2,
                      'AD_PRES', salary * 1.3,
                      salary) AS aumento_salarial
  FROM hr.employees
 WHERE employee_id = 100
    OR job_id IN ('IT_PROG', 'AD_VP');