MySQL 实现点餐系统的订单评价管理功能

CREATE DATABASE order_evaluation;

USE order_evaluation;

CREATE TABLE evaluation (
  id INT(11) NOT NULL AUTO_INCREMENT,
  order_id INT(11) NOT NULL,
  rating FLOAT NOT NULL,
  comment TEXT,
  PRIMARY KEY (id),
  FOREIGN KEY (order_id) REFERENCES orders(id)
);

CREATE TABLE orders (
  id INT(11) NOT NULL AUTO_INCREMENT,
  customer_id INT(11) NOT NULL,
  order_time TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
  total_price DECIMAL(8,2) NOT NULL,
  PRIMARY KEY (id)
);

INSERT INTO orders (customer_id, total_price) VALUES (1, 50.00);
INSERT INTO orders (customer_id, total_price) VALUES (2, 25.00);
INSERT INTO orders (customer_id, total_price) VALUES (3, 35.00);

INSERT INTO evaluation (order_id, rating, comment) VALUES (1, 4.5, '餐品非常美味，服务也很好！');
INSERT INTO evaluation (order_id, rating, comment) VALUES (2, 3.0, '餐品一般般，服务稍微有些慢。');
INSERT INTO evaluation (order_id, rating, comment) VALUES (3, 5.0, '完美的用餐体验，非常满意！');

SELECT o.id, o.order_time, o.total_price, e.rating, e.comment
FROM orders o
LEFT JOIN evaluation e ON o.id = e.order_id;