Oracle存储过程和函数简单示例（二）

 

--------------------------存储过程练习-------------------------------------------
--存储过程基本语法结构，我在运行过程中，总会出现已在sql窗口建了某张表，但在命令窗口查询说不存在，
--主要问题在于用户切换导致的用户不同------
DECLARE
  v_ename emp.ename%TYPE;
BEGIN
  SELECT ename INTO v_ename FROM emp WHERE empno = &empno;
  dbms_output.put_line('员工姓名:' || v_ename);
  EXCEPTION
    WHEN NO_DATA_FOUND 
    THEN dbms_output.put_line('查无此人!');  
END;

/**
    条件判断
    IF boolean THEN executable END IF;
    IF boolean THEN executable ELSE executable END IF;
    IF boolean THEN executable ELSIF boolean THEN executable ELSE executable END IF;  
*/
/**
    循环 (LOOP WHILE FOR)
*/
-- LOOP
DECLARE
   j NUMBER := 0;
BEGIN
   j := 1;
   LOOP
     dbms_output.put_line(j);
     EXIT WHEN j >= 7;  
     j := j + 1;
   END LOOP;
END;

-- WHILE
DECLARE
   j NUMBER := 0;
BEGIN
   j := 1;
   WHILE j <= 8
   LOOP
       dbms_output.put_line(j || '---');
       j := j+1;
   END LOOP;
END;

-- FOR
DECLARE 
  j NUMBER := 0;
BEGIN
  FOR j IN 1..8
  LOOP
    dbms_output.put_line(j || '---');
  END LOOP;  
END;

/**
   存储过程.PROCEDURE
   参数形式三种 (in, outm in out)
*/

-- 示例一
CREATE OR REPLACE PROCEDURE PROC1(i IN NUMBER)
AS 
 a VARCHAR2(50);
BEGIN
  a := '';
  FOR j IN 1..i 
  LOOP
    a := a || '*';
    dbms_output.put_line(a);
  END LOOP;
END;  

-- 两种方式调用存储过程 1 通过exec执行 2 通过块执行
-- exec PROC1(4);
BEGIN
  PROC1(7);
END;
----------------------运行------------------------------------------
SQL> CREATE OR REPLACE PROCEDURE PROC1(i IN NUMBER)
  2  AS
  3   a VARCHAR2(50);
  4  BEGIN
  5    a := '';
  6    FOR j IN 1..i
  7    LOOP
  8      a := a || '*';
  9      dbms_output.put_line(a);
 10    END LOOP;
 11  END;
 12  /

Procedure created

SQL> 
SQL> BEGIN
  2    PROC1(7);
  3  END;
  4  /

*
**
***
****
*****
******
*******
PL/SQL procedure successfully completed
--示例二
CREATE OR REPLACE PROCEDURE PROC2(i OUT NUMBER)
AS
BEGIN
  i := 100;
  dbms_output.put_line(i);
END;

DECLARE
 k NUMBER;
BEGIN
  PROC2(K);
  dbms_output.put_line(k);
END; 
----------------------------运行--------------------------------
SQL> CREATE OR REPLACE PROCEDURE PROC2(i OUT NUMBER)
  2  AS
  3  BEGIN
  4    i := 100;
  5    dbms_output.put_line(i);
  6  END;
  7  /

Procedure created

SQL> 
SQL> DECLARE
  2   k NUMBER;
  3  BEGIN
  4    PROC2(K);
  5    dbms_output.put_line(k);
  6  END;
  7  /

100
100
PL/SQL procedure successfully completed

-- 示例三

CREATE OR REPLACE PROCEDURE PROC3(p1 IN OUT NUMBER , p2 IN OUT NUMBER)
AS
  v_temp NUMBER;
BEGIN
  v_temp := p1;
  p1 :=  p2;
  p2 := v_temp;
END;

DECLARE 
num1 NUMBER := 10; 
num2 NUMBER := 20;
BEGIN
  PROC3(num1, num2);
  dbms_output.put_line(num1); 
  dbms_output.put_line(num2); 
END;
------------------------------------------------------------------------------
SQL> CREATE OR REPLACE PROCEDURE PROC3(p1 IN OUT NUMBER , p2 IN OUT NUMBER)
  2  AS
  3    v_temp NUMBER;
  4  BEGIN
  5    v_temp := p1;
  6    p1 :=  p2;
  7    p2 := v_temp;
  8  END;
  9  /

Procedure created

SQL> 
SQL> DECLARE
  2  num1 NUMBER := 10;
  3  num2 NUMBER := 20;
  4  BEGIN
  5    PROC3(num1, num2);
  6    dbms_output.put_line(num1);
  7    dbms_output.put_line(num2);
  8  END;
  9  /

20
10
PL/SQL procedure successfully completed

--函数--
/**
     函数：（函数是可以返回值的命名的PL/SQL 子程序）
     CREATE [OR REPLACE] FUNCTION  [(PARAM...)]
     RETURN  IS|AS 
     [LOCAL DECLARATIONS]
     BEGIN
       EXECUTABLE STATEMENTS;
       RETURN RESULT;
       EXCEPTION 
         EXCEPTION HANDLERS; 
     END;
*/

-- 001 要求：创建一个函数,可以接受用户输入的学号，得到该学生的名次，输出名次。
drop table STUDENT;
CREATE TABLE STUDENT (STU_NO NUMBER(3), NAME VARCHAR2(10), SCORE NUMBER(3));
INSERT INTO STUDENT VALUES (1 , '小小', 99);
INSERT INTO STUDENT VALUES (2 , '小G',  80);
INSERT INTO STUDENT VALUES (3 , '诺诺', 98);
INSERT INTO STUDENT VALUES (4 , '小北', 79);
COMMIT;
SELECT * FROM STUDENT;
CREATE OR REPLACE FUNCTION FUNC1(SNO INT) RETURN INT
AS
 v_score NUMBER;
 v_mingci NUMBER;
BEGIN
 SELECT SCORE INTO v_score FROM STUDENT WHERE STU_NO = SNO;
 SELECT COUNT(*) INTO v_mingci FROM STUDENT WHERE SCORE > v_score;
 v_mingci := v_mingci + 1;
 RETURN v_mingci;
END;

SELECT FUNC1(3) FROM DUAL;
--------------------------运行---------------------------------------------
SQL> CREATE OR REPLACE FUNCTION FUNC1(SNO INT) RETURN INT
  2  AS
  3   v_score NUMBER;
  4   v_mingci NUMBER;
  5  BEGIN
  6   SELECT SCORE INTO v_score FROM STUDENT WHERE STU_NO = SNO;
  7   SELECT COUNT(*) INTO v_mingci FROM STUDENT WHERE SCORE > v_score;
  8   v_mingci := v_mingci + 1;
  9   RETURN v_mingci;
 10  END;
 11  /

Function created

SQL> SELECT FUNC1(3) FROM DUAL;

  FUNC1(3)
----------
         2