The NULL statement only passes control to the next statement.
In the following code, the NULL statement emphasizes that only salespersons receive commissions.
SQL> SQL> drop TABLE emp; SQL>-- from w ww. j a v a2 s. c om SQL> CREATE TABLE emp( 2 empid NUMBER(6), 3 first_name VARCHAR2(20), 4 last_name VARCHAR2(25)) ; SQL> SQL> INSERT INTO emp VALUES( 100, 'Steven', 'King'); SQL> INSERT INTO emp VALUES( 101, 'Mary', 'Smith'); SQL> DECLARE 2 v_job_id VARCHAR2(10); 3 v_emp_id NUMBER(6) := 110; 4 BEGIN 5 SELECT empid INTO v_job_id 6 FROM emp 7 WHERE empid = v_emp_id; 8 9 IF v_job_id = '001' THEN 10 UPDATE emp 11 SET commission_pct = commission_pct * 1.2; 12 ELSE 13 NULL; -- Employee is not a sales rep 14 END IF; 15 END; 16 / SQL>