mysql 两个表去重

SELECT DISTINCT t1.column1, t2.column2
FROM table1 t1
JOIN table2 t2 ON t1.common_column = t2.common_column;

SELECT t1.column1, t2.column2
FROM table1 t1
JOIN table2 t2 ON t1.common_column = t2.common_column
GROUP BY t1.column1, t2.column2;

SELECT t1.column1, t2.column2
FROM table1 t1
JOIN (
    SELECT DISTINCT common_column, column2
    FROM table2
) t2 ON t1.common_column = t2.common_column;

-- orders 表结构
CREATE TABLE orders (
    order_id INT PRIMARY KEY,
    product_id INT,
    order_date DATE
);

-- products 表结构
CREATE TABLE products (
    product_id INT PRIMARY KEY,
    product_name VARCHAR(255)
);

-- 插入示例数据
INSERT INTO orders (order_id, product_id, order_date) VALUES
(1, 101, '2023-01-01'),
(2, 102, '2023-01-02'),
(3, 101, '2023-01-03');

INSERT INTO products (product_id, product_name) VALUES
(101, 'Product A'),
(102, 'Product B');

SELECT DISTINCT p.product_name, o.order_date
FROM orders o
JOIN products p ON o.product_id = p.product_id;