Question

我需要让用户输入值并使用pl / sql函数返回多个值，我设法只返回一个值并且无法提升用户输入值。我需要客户5将订单从30增加到200.允许用户输入：

1）customer_ID和的数字4 2）100更新数量。

并在更改之前和之后打印输出，这样的事情 ..

Enter value for customer_id: 4
old   7:   l_customer_id :=&customer_ID;
new   7:   l_customer_id :=4;
Enter value for new_quantity: 520
old   9:   l_new_quantity :=&new_quantity;
new   9:   l_new_quantity :=520;
Old quangtity: 100
New quantity: 520
Quantity changed from 100 to 520 (+420)

我的代码但只返回旧的数量值

CREATE OR REPLACE FUNCTION update_sales
( 
  p_customer_id IN sales.customer_id%type,
  p_product_id IN sales.product_id%type,
  p_new_quantity IN sales.quantity%type
)
RETURN sales.quantity%type
AS
  l_old_quantity sales.quantity%type;
BEGIN
  SELECT quantity
  INTO l_old_quantity
  FROM sales
  WHERE customer_id = p_customer_id
  AND product_id = p_product_id;

  UPDATE sales
  SET quantity = p_new_quantity
  WHERE customer_id = p_customer_id
  AND product_id = p_product_id;

  RETURN l_old_quantity;
END;
/

DECLARE
  l_old_quantity sales.quantity%type;
BEGIN
  l_old_quantity := update_sales(5, 4, 200);
  dbms_output.put_line('Quantity was ' || l_old_quantity);
END;
/

产品表

Create table sales (customer_ID number(10), product_ID number(10), quantity number(10));

INSERT INTO sales (customer_ID, product_ID, quantity) Values(3,1,23);
INSERT INTO sales (customer_ID, product_ID, quantity) Values(1,2,34);
INSERT INTO sales (customer_ID, product_ID, quantity) Values(1,3,654);
INSERT INTO sales (customer_ID, product_ID, quantity) Values(3,7,32);
INSERT INTO sales (customer_ID, product_ID, quantity) Values(4,3,23);
INSERT INTO sales (customer_ID, product_ID, quantity) Values(3,3,111);
INSERT INTO sales (customer_ID, product_ID, quantity) Values(5,4,6);

请咨询

Answer 1

通常，无法从函数返回多个变量。

但是，您有以下两种选择：

选项1： 不建议使用功能：

您可以在函数参数中使用OUT类型：

CREATE OR REPLACE FUNCTION update_sales
( 
  p_customer_id_in IN sales.customer_id%type,
  p_product_id_in IN sales.product_id%type,
  p_new_quantity_in IN  sales.quantity%type
  p_customer_id_out OUT sales.customer_id%type,
  p_product_id_out OUT sales.product_id%type,
  p_old_quantity_out OUT sales.quantity%type
)
....
--The remaining of your function

对于customer_id，如果您愿意，可以将IN OUT类型用于一个变量。

然后当你打电话时，你会使用这样的东西：

v_result:=update_sales(p_customer_id_in => 5,  p_product_id_in => 4, p_new_quantity_in => 200,  p_customer_id_out => v1_out,  p_product_id_out => v2_out,  p_new_quantity_out => v3_out );

选项2：
使用record类型要做到这一点，首先需要定义类型包含要返回的三个变量，如下所示：

TYPE new_type is record(l_customer_id sales.customer_id%type, l_old_quantity sales.quantity%type, l_new_quantity  sales.quantity%type);

然后你可以在你的函数中使用它，如下所示：

CREATE OR REPLACE FUNCTION update_sales
( 
 p_customer_id IN sales.customer_id%type,
 p_product_id IN sales.product_id%type,
 p_new_quantity IN sales.quantity%type
)
RETURN new_type AS 

new_type_variable newtype;
....

BEGIN
--You can refer to the fields of the records using (.) 
-- e.g., new_type_variable.l_customer_id

 RETURN new_type_variable ;
END;

基于第一种方法的完整功能

CREATE OR REPLACE FUNCTION update_sales
( 
  p_customer_id_in IN sales.customer_id%type,
  p_product_id_in IN sales.product_id%type,
  p_new_quantity_in IN  sales.quantity%type,
  p_customer_id_out OUT sales.customer_id%type,
  p_product_id_out OUT sales.product_id%type,
  p_old_quantity_out OUT sales.quantity%type
)
RETURN sales.quantity%type
AS
  l_old_quantity sales.quantity%type;
BEGIN
  SELECT quantity
  INTO p_old_quantity_out
  FROM sales
  WHERE customer_id = p_customer_id_in
  AND product_id = p_product_id_in;

  UPDATE sales
  SET quantity = p_new_quantity_in
  WHERE customer_id = p_customer_id_in
  AND product_id = p_product_id_in;

  RETURN l_old_quantity;
END;
/

测试

CREATE TABLE TEMP_TEST(a varchar2(100));

DECLARE 
V_RESULT NUMBER;
v1_out  sales.customer_id%type;
v2_out  sales.product_id%type;
v3_out  sales.quantity%type;
BEGIN
DBMS_OUTPUT.ENABLE(10000);
DBMS_OUTPUT.PUT_LINE('TEST');

v_result:=update_sales
(
  p_customer_id_in => 5,
  p_product_id_in => 4,
  p_new_quantity_in => 200,
  p_customer_id_out => v1_out,
  p_product_id_out => v2_out,
  p_old_quantity_out => v3_out
 );
  INSERT INTO TEMP_TEST VALUES ('p_customer_id_out = ' ||v1_out);
  INSERT INTO TEMP_TEST VALUES ('p_product_id_out = '||v2_out);
  INSERT INTO TEMP_TEST VALUES ('p_old_quantity_out = '||v3_out);
  COMMIT;

END;
/

SELECT * FROM TEMP_TEST;

结果：

p_customer_id_out =     
p_product_id_out =     
p_old_quantity_out = 200

因为在您的功能中，您只为p_old_quantity_out

指定了值

Answer 2

在您的示例中，我实际上不明白为什么您需要返回新数量，因为这是您实际提交给函数的参数。

然而，我只是使用一个过程而不是一个函数，并根据需要返回尽可能多的OUT参数：

CREATE OR REPLACE FUNCTION update_sales
( p_customer_id IN sales.customer_id%type,
, p_product_id IN sales.product_id%type,
, p_new_quantity IN sales.quantity%type,
, p_old_quantity OUT sales.quantity%type
, p_transaction_date OUT DATE /* just as an example */
)
AS
BEGIN
  SELECT quantity
  INTO p_old_quantity
  FROM sales
  WHERE customer_id = p_customer_id
  AND product_id = p_product_id;

  UPDATE sales
  SET quantity = p_new_quantity
  WHERE customer_id = p_customer_id
  AND product_id = p_product_id;

  p_transaction_date := SYSDATE;
END;
/

DECLARE
  l_old_quantity sales.quantity%type;
  l_transaction_date DATE;
BEGIN
  update_sales(5, 4, 200, l_old_quantity, l_current_date);
  dbms_output.put_line('Quantity was ' || l_old_quantity);
  dbms_output.put_line('Transaction date was ' || l_transaction_date);
END;
/

返回多个值pl / sql函数

2 个答案: