PLSQL Language Referenc-PL/SQL控制語句-順序控制語句-NULL

DECLARE

    v_job_id  VARCHAR2(10);

    v_emp_id  NUMBER(6) := 110;

BEGIN

    SELECT job_id INTO v_job_id

    FROM employees

    WHERE employee_id = v_emp_id;

    IF v_job_id = 'SA_REP' THEN

        UPDATE employees

        SET commission_pct = commission_pct * 1.2;

    ELSE

        --對應第2點

        NULL;  -- 員工如果不是'SA_REP'

    END IF;

END;

CREATE OR REPLACE PROCEDURE award_bonus (

    emp_id NUMBER,

    bonus NUMBER

) AS

BEGIN   

  NULL;  -- 佔位符

  -- 如果不加NULL語句，則產生編譯錯誤

END award_bonus;

-- AUTHID DEFINER設定呼叫許可權

CREATE OR REPLACE PROCEDURE print_grade (grade CHAR) AUTHID DEFINER AS

BEGIN

    CASE grade

        WHEN 'A' THEN DBMS_OUTPUT.PUT_LINE('優秀');

        WHEN 'B' THEN DBMS_OUTPUT.PUT_LINE('良好');

        WHEN 'C' THEN DBMS_OUTPUT.PUT_LINE('好');

        WHEN 'D' THEN DBMS_OUTPUT.PUT_LINE('及格');

        WHEN 'F' THEN DBMS_OUTPUT.PUT_LINE('不及格');

        --無需處理

        ELSE NULL;

    END CASE;

END;