mysql两个表拼接

-- 创建示例表
CREATE TABLE users (
    id INT PRIMARY KEY,
    name VARCHAR(50)
);

CREATE TABLE orders (
    id INT PRIMARY KEY,
    user_id INT,
    amount DECIMAL(10, 2)
);

-- 插入示例数据
INSERT INTO users (id, name) VALUES (1, 'Alice'), (2, 'Bob');
INSERT INTO orders (id, user_id, amount) VALUES (1, 1, 100.00), (2, 1, 200.00), (3, 2, 150.00);

-- 内连接示例
SELECT users.name, orders.amount
FROM users
INNER JOIN orders ON users.id = orders.user_id;

-- 左连接示例
SELECT users.name, orders.amount
FROM users
LEFT JOIN orders ON users.id = orders.user_id;

-- 右连接示例
SELECT users.name, orders.amount
FROM users
RIGHT JOIN orders ON users.id -orders.user_id;

-- 全连接示例（MySQL不支持全连接，但可以通过UNION实现类似效果）
SELECT users.name, orders.amount
FROM users
LEFT JOIN orders ON users.id = orders.user_id
UNION
SELECT users.name, orders.amount
FROM users
RIGHT JOIN orders ON users.id = orders.user_id;