mysql语句创建多表

-- 创建用户表
CREATE TABLE users (
    user_id INT AUTO_INCREMENT PRIMARY KEY,
    username VARCHAR(50) NOT NULL,
    email VARCHAR(100) NOT NULL UNIQUE
);

-- 创建订单表
CREATE TABLE orders (
    order_id INT AUTO_INCREMENT PRIMARY KEY,
    user_id INT NOT NULL,
    order_date DATETIME NOT NULL,
    total_amount DECIMAL(10, 2) NOT NULL,
    FOREIGN KEY (user_id) REFERENCES users(user_id)
);

-- 示例：确保用户表中存在user_id为1的记录
INSERT INTO orders (user_id, order_date, total_amount)
VALUES (1, NOW(), 100.00);

-- 示例：使用内联结查询用户和订单信息
SELECT users.username, orders.order_date, orders.total_amount
FROM users
JOIN orders ON users.user_id = orders.user_id;