mysql 函数多行输出

DELIMITER //

CREATE FUNCTION CalculateTotalPrice(order_id INT)
RETURNS DECIMAL(10, 2)
DETERMINISTIC
BEGIN
    DECLARE total DECIMAL(10, 2);
    SELECT SUM(price * quantity) INTO total
    FROM order_items
    WHERE order_id = CalculateTotalPrice.order_id;
    RETURN total;
END //

DELIMITER ;

SELECT order_id, CalculateTotalPrice(order_id) AS total_price
FROM orders;

DELIMITER //

CREATE PROCEDURE GetOrderItems(order_id INT)
BEGIN
    SELECT * FROM order_items WHERE order_id = GetOrderItems.order_id;
END //

DELIMITER ;

CALL GetOrderItems(1);

SELECT *
FROM (
    SELECT * FROM order_items WHERE order_id = 1
) AS subquery;