text: syntax:
  
  DECODE(col|expression, search1, result1 
   [, search2, result2,...,][, default])
  
  Example :
  
  SELECT last_name, job_id, salary,
     DECODE(job_id, ’IT_PROG’, 1.10*salary,
      ’ST_CLERK’, 1.15*salary,
      ’SA_REP’, 1.20*salary,salary) 
       REVISED_SALARY FROM employees;
  