Max()花费了相当长的时间，有没有其他方法来编写这个查询？

CREATE INDEX idx_order_date ON orders(order_date);

SELECT MAX(order_date) AS latest_order_date
FROM (
    SELECT order_date
    FROM orders
    ORDER BY order_date DESC
    LIMIT 1
) AS subquery;

SELECT DISTINCT ON (order_date) order_date
FROM orders
ORDER BY order_date DESC;

CREATE TEMPORARY TABLE temp_orders AS
SELECT order_date
FROM orders
ORDER BY order_date DESC
LIMIT 1;

SELECT MAX(order_date) FROM temp_orders;

EXPLAIN SELECT MAX(order_date) FROM orders;

SELECT customer_id, MAX(order_date) AS latest_order_date
FROM orders
GROUP BY customer_id;

-- 创建示例表
CREATE TABLE orders (
    order_id INT PRIMARY KEY,
    customer_id INT,
    order_date DATE
);

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

-- 使用子查询优化 MAX() 函数
SELECT MAX(order_date) AS latest_order_date
FROM (
    SELECT order_date
    FROM orders
    ORDER BY order_date DESC
    LIMIT 1
) AS subquery;