连接3个表的结果不正确

-- 错误的连接条件
SELECT *
FROM table1
JOIN table2 ON table1.id = table3.id;  -- 应该是 table1.id = table2.id

-- 正确的连接条件
SELECT *
FROM table1
JOIN table2 ON table1.id = table2.id
JOIN table3 ON table2.id = table3.id;

-- 确保连接列的数据类型和值一致
SELECT *
FROM table1
JOIN table2 ON table1.id = CAST(table2.id AS INT)
JOIN table3 ON table2.id = CAST(table3.id AS INT);

-- 错误的表顺序
SELECT *
FROM table1
JOIN table3 ON table1.id = table3.id
JOIN table2 ON table3.id = table2.id;

-- 正确的表顺序
SELECT *
FROM table1
JOIN table2 ON table1.id = table2.id
JOIN table3 ON table2.id = table3.id;

-- 内连接
SELECT *
FROM table1
INNER JOIN table2 ON table1.id = table2.id
INNER JOIN table3 ON table2.id = table3.id;

-- 左连接
SELECT *
FROM table1
LEFT JOIN table2 ON table1.id = table2.id
LEFT JOIN table3 ON table2.id = table3.id;

CREATE TABLE users (
    id INT PRIMARY KEY,
    name VARCHAR(100)
);

CREATE TABLE orders (
    id INT PRIMARY KEY,
    user_id INT,
    product_id INT
);

CREATE TABLE products (
    id INT PRIMARY KEY,
    name VARCHAR(100),
    price DECIMAL(10, 2)
);

SELECT u.name AS user_name, p.name AS product_name, p.price
FROM users u
JOIN orders o ON u.id = o.user_id
JOIN products p ON o.product_id = p.id;