项目构造:
预备表和数据:
CREATE TABLE orders(
order_id INT PRIMARY KEY AUTO_INCREMENT,
order_no VARCHAR(20),
order_price FLOAT
);
INSERT INTO orders(order_no, order_price) VALUES("aaaa", 23);
INSERT INTO orders(order_no, order_price) VALUES("bbbb", 33);
INSERT INTO orders(order_no, order_price) VALUES("cccc", 22);CREATE TABLE orders(
order_id IN