IF-THEN-STATEMENT IN ORACLE

The following is the example using IF_Then statement  in an oracle
 Note:- Once a condition is found is true,then if-Then-statement will execute the corresponding code and not evaluate the conditions any further.

SQL> DECLARE
  2    V_NAME  EMPLOYEES.LAST_NAME%TYPE;
  3    V_SAL   EMPLOYEES.SALARY%TYPE;
  4    V_BONUS V_SAL%TYPE;
  5  BEGIN
  6    SELECT LAST_NAME,SALARY
  7    INTO   V_NAME,V_SAL
  8    FROM   EMPLOYEES
  9    WHERE  EMPLOYEE_ID=&EMPNO;
 10
 11    IF V_SAL   >= 20000 THEN
 12       V_BONUS := V_SAL*.2;
 13    ELSIF V_SAL>=15000 THEN
 14       V_BONUS := V_SAL*.3;
 15    ELSIF V_SAL>= 10000 THEN
 16       V_BONUS := V_SAL *.4;
 17    ELSE
 18       V_BONUS := V_SAL*.5;
 19    END IF;
 20
 21    DBMS_OUTPUT.PUT_LINE('BONUS OF '||V_NAME||' IS '||V_BONUS);
 22  END;
 23  /
Enter value for empno: 200
old   9:   WHERE  EMPLOYEE_ID=&EMPNO;
new   9:   WHERE  EMPLOYEE_ID=200;

PL/SQL procedure successfully completed.

SQL> set serveroutput on
SQL> /
Enter value for empno: 200
old   9:   WHERE  EMPLOYEE_ID=&EMPNO;
new   9:   WHERE  EMPLOYEE_ID=200;
BONUS OF Whalen IS 2200

PL/SQL procedure successfully completed.