Oracle变量、输入输出、SELECT INTO、%TYPE与%ROWTYPE详解

DECLARE
 
  --声明的地方(声明变量，常量，游标等等)，这一块不是必须的。
BEGIN

  --代码的执行的逻辑块(就是要做什么) 
END;

BEGIN
  dbms_output.put_line('你好');
END;

BEGIN
  dbms_output.put_line('Hello World');
  dbms_output.put_line('你好');
END;

DECLARE
  v1 varchar2(20);
  v2 date;
BEGIN
  v1 := 'Hello';
  dbms_output.put_line(v1);
  v2 := to_date('20220101', 'yyyymmdd');
  dbms_output.put_line(v2);
END;

DECLARE
  v1 varchar2(20);
BEGIN
  v1 := 'Hello';
  -- dbms_output.put_line(v1);
  v1 := '你好';
  dbms_output.put_line(v1);
END;

-- 方法一：
DECLARE
  v1 number;
  v2 varchar2(20);
BEGIN
  v1 := 10;
  dbms_output.put_line(v1);
  v2 := TO_CHAR(SYSDATE, 'YYYY-MM-DD');
  dbms_output.put_line(v2);
END;

-- 方法二：
DECLARE
  v1 number := 10;
  v2 varchar2(20) := TO_CHAR(SYSDATE, 'YYYY-MM-DD');
BEGIN
  dbms_output.put_line(v1 || chr(10) || v2);
END;

DECLARE
  v1 number := &input; -- 变量值名称可自定义
  v2 number;
BEGIN
  v2 := power(v1, 3);
  -- v2:=v1*v1*v1;
  dbms_output.put_line(v2);
END;

DECLARE
  v1 varchar2(20) := '&input1';
  v2 DATE := &input2;
BEGIN
  dbms_output.put_line(v1 || CHR(10) || v2);
END;

DECLARE
  v1 number := &input1;
  v2 number := &input2;
BEGIN
  dbms_output.put_line(v1 + v2);
  dbms_output.put_line(v1 - v2);
  dbms_output.put_line(v1 * v2);
  dbms_output.put_line(v1 / v2);
END;

DECLARE
  v1    number := &input;
  v_sal number;
BEGIN
  select sal into v_sal from emp where empno = v1;
  dbms_output.put_line(v_sal);
END;

DECLARE
  v1         number := &input;
  v_ename    varchar2(20);
  v_sal      number;
  v_hiredate date;
BEGIN
  select ename, sal, hiredate
    into v_ename, v_sal, v_hiredate
    from emp
   where empno = v1;
  dbms_output.put_line(v_ename || ',' || v_sal || ',' || TO_CHAR(v_hiredate, 'YYYY-MM-DD'));
END;

DECLARE
  v1        number := &input;
  v_avg_sal number;
BEGIN
  select round(avg(sal + nvl(comm, 0)),2) avg_sal
    into v_avg_sal  
    from emp
   where deptno = v1
   group by deptno;
  dbms_output.put_line(v1 || '号部门的平均薪资为：' || v_avg_sal);
END;

DECLARE
  v1      varchar2(20) := '&input';
  v_empno number;
  v_job   varchar2(20);
BEGIN
  select empno, job into v_empno, v_job from emp where ename = v1;
  dbms_output.put_line(v_empno || ',' || v_job);
END;

DECLARE
  v_EMPNO    EMP.EMPNO%TYPE := &input;
  v_ENAME    EMP.ENAME%TYPE;
  v_SAL      EMP.SAL%TYPE;
  v_HIREDATE EMP.HIREDATE%TYPE;
BEGIN
  select ENAME, SAL, HIREDATE
    into v_ENAME, v_SAL, v_HIREDATE
    from EMP
   where EMPNO = v_EMPNO;
  dbms_output.put_line(v_ENAME || '的薪资是：' || v_SAL || '入职时间：' ||
                       TO_CHAR(v_HIREDATE,'YYYY-MM-DD'));
END;

DECLARE
  v_emp emp%ROWTYPE;
BEGIN
  v_emp.EMPNO := &INPUT;
  select ENAME, SAL, HIREDATE
    into v_emp.ENAME, v_emp.SAL, v_emp.HIREDATE
    from EMP
   where EMPNO = v_emp.EMPNO;
  dbms_output.put_line(v_emp.ENAME || '的薪资是：' || v_emp.SAL || '入职时间：' ||
                       TO_CHAR(v_emp.HIREDATE, 'YYYY-MM-DD'));
END;

-- %TYPE
DECLARE
  v_ENAME EMP.ENAME%TYPE := '&input';
  v_EMPNO EMP.EMPNO%TYPE;
  v_JOB   EMP.JOB%TYPE;
BEGIN
  select EMPNO, JOB into v_EMPNO, v_JOB from EMP where ENAME = v_ENAME;
  dbms_output.put_line(v_ENAME || '的工号是：' || v_EMPNO || '岗位是：' || v_JOB);
END;


-- %ROWTYPE
DECLARE
  v_EMP EMP%ROWTYPE;
BEGIN
  v_EMP.ENAME := '&INPUT';
  select EMPNO, JOB
    into v_EMP.EMPNO, v_EMP.JOB
    from EMP
   where ENAME = v_EMP.ENAME;
  dbms_output.put_line(v_EMP.ENAME || '的工号是：' || v_EMP.EMPNO || '岗位是：' ||
                       v_EMP.JOB);
END;