CREATE TABLE orders (
id INT PRIMARY KEY,
user_id INT,
amount DECIMAL(10,2),
created_at DATETIME,
INDEX idx_user_created (user_id, created_at)
);
SELECT user_id, created_at, amount
FROM orders
WHERE user_id = 100 AND created_at > '2024-01-01'
ORDER BY created_at DESC;
关于该查询的索引使用，以下说法正确的是：
