如何在mysql中形成一个存储过程，它可以先检查多个表上的多个值，然后如果为真则插入到db中
[英]how can I form a stored procedure in mysql, which can first check multiple values on multiple tables and then insert into db if true
问题描述
实际问题陈述如下：
• 产品（prod_id、prod_name、qty_on_hand）
• 订单（cust_id、prod_id、order_date、qty_ordered）
• 客户（cust_id、cust_name、电话、地址）
“编写一个存储过程以将 cust_id、prod_id 和 qty_ordered 作为输入。程序应检查是否可以满足特定客户的订单，如果是，则插入新订单并更新手头的产品数量。如果无法完成订单。Output 参数必须具有 qty_on_hand 的更新值”
我是 plsql 的新手，所以请忽略愚蠢的错误。 我试着编写这样的代码：
delimiter $$
-- creating procedure
CREATE PROCEDURE order_request( cust_id int, prod_id int, qty_ordered int)
BEGIN
IF( customer.cust_id != cust_id AND product.prod_id != prod_id AND qty_ordered > product.qty_on_hand) THEN
SELECT 'invalid details' ;
ELSE INSERT INTO `orders` (`cust_id`, `prod_id`, `order_date`, `qty_ordered`) VALUES (cust_id, prod_id, current_date(), qty_ordered) ;
END IF ;
END $$
CALL order_request(3,3,2)$$
显示错误： unknown table customer in field list
1 条回复
1楼 Priyank Jain 0 已采纳 2022-09-29 20:27:24
我已经解决了这个问题。 这是解决方案：
CREATE DATABASE shopping;
USE shopping;
CREATE TABLE product( prod_id INT PRIMARY KEY, prod_name varchar(20), qty_on_hand INT CHECK(qty_on_hand >= 0));
CREATE TABLE customer( cust_id INT PRIMARY KEY, cust_name varchar(20), phone INT, address varchar(20) );
-- product table insertion
INSERT INTO `product` (`prod_id`, `prod_name`, `qty_on_hand`) VALUES ('1', 'mug', '2');
INSERT INTO `product` (`prod_id`, `prod_name`, `qty_on_hand`) VALUES ('2', 'bowl', '15');
INSERT INTO `product` (`prod_id`, `prod_name`, `qty_on_hand`) VALUES ('3', 'plate', '7');
INSERT INTO `product` (`prod_id`, `prod_name`, `qty_on_hand`) VALUES ('4', 'fork', '40');
INSERT INTO `product` (`prod_id`, `prod_name`, `qty_on_hand`) VALUES ('5', 'spoon', '30');
-- customer table insertion
INSERT INTO `customer` (`cust_id`, `cust_name`, `phone`, `address`) VALUES ('1', 'duke', '1212121212', 'pune');
INSERT INTO `customer` (`cust_id`, `cust_name`, `phone`, `address`) VALUES ('2', 'finn', '190120138', 'waterland');
INSERT INTO `customer` (`cust_id`, `cust_name`, `phone`, `address`) VALUES ('3', 'buck', '98989898', 'delhi');
INSERT INTO `customer` (`cust_id`, `cust_name`, `phone`, `address`) VALUES ('4', 'larry', '738197232', 'jaipur');
INSERT INTO `customer` (`cust_id`, `cust_name`, `phone`, `address`) VALUES ('5', 'edna', '184194791', 'mumbai');
CREATE TABLE orders( cust_id INT, prod_id INT, order_date DATE, qty_ordered INT CHECK(qty_ordered > 0) , FOREIGN KEY (cust_id) REFERENCES customer(cust_id), FOREIGN KEY (prod_id) REFERENCES product(prod_id));
-- orders table insertion
INSERT INTO `orders` (`cust_id`, `prod_id`, `order_date`, `qty_ordered`) VALUES ('1', '2', '2022-09-15', '2');
delimiter $$
-- creating procedure
CREATE PROCEDURE order_request( cust_id_param INT, prod_id_param INT, qty_ordered_param INT)
BEGIN
IF EXISTS (SELECT cust_id,prod_id,qty_on_hand FROM customer,product WHERE cust_id = cust_id_param AND prod_id = prod_id_param AND qty_on_hand >= qty_ordered_param)
THEN INSERT INTO `orders` (`cust_id`, `prod_id`, `order_date`, `qty_ordered`) VALUES (cust_id_param, prod_id_param, current_date(), qty_ordered_param);
UPDATE `product` SET product.qty_on_hand = qty_on_hand - qty_ordered_param WHERE prod_id = prod_id_param ;
ELSE SELECT 'invalid details' ;
END IF ;
END $$
CALL order_request(1,1,2)$$ -- valid
CALL order_request(3,2,14)$$ -- valid
CALL order_request(5,4,4)$$ -- valid
CALL order_request(10,10,2)$$ -- invalid
select * from orders$$
select * from product$$
-- creating the funtion
CREATE FUNCTION order_details (cust_id_param INT, prod_id_param INT ) RETURNS INT
BEGIN
DECLARE ans int;
SELECT SUM(qty_ordered) INTO ans FROM orders WHERE cust_id = cust_id_param AND prod_id = prod_id_param;
RETURN ans;
END$$
-- calling the funtion
SELECT order_details(5,4)$$
问题未解决？试试以下方法：
如何为存储过程使用字符串ID插入多个记录？
[英]How can I insert multiple records using a string ids for a stored procedure?
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