PLSQL Language Referenc-PL/SQL動態SQL-練習：在USING子句中未初始化的變數表示NULL

-- 11g12_07_03.sql

CREATE TABLE EmployeeTemp AS SELECT * FROM EMPLOYEES;

-- 1執行11g12_07_03.tst前檢視EmployeeTemp

SELECT * FROM EmployeeTemp;

-- 執行11g12_07_03.tst

-- 1

-- 11g12_07_03.tst

DECLARE

    -- 在執行時自動設定為NULL 

    aNULL  CHAR(1); 

BEGIN

    EXECUTE IMMEDIATE 'UPDATE EmployeeTemp SET commission_pct = :x'

    USING aNULL;

    COMMIT;

END;