结合使用sum和product公式进行mysql计算

-- 计算总销售额
SELECT SUM(quantity * price) AS total_sales FROM sales;

-- 计算总销售数量
SELECT SUM(quantity) AS total_quantity FROM sales;

DELIMITER //

CREATE FUNCTION ProductOfNumbers(numbers FLOAT) RETURNS FLOAT
DETERMINISTIC
BEGIN
    DECLARE result FLOAT DEFAULT 1;
    DECLARE i INT DEFAULT 1;
    DECLARE num FLOAT;
    WHILE i <= numbers DO
        SET num = SUBSTRING_INDEX(SUBSTRING_INDEX(numbers, ',', i), ',', -1);
        SET result = result * num;
        SET i = i + 1;
    END WHILE;
    RETURN result;
END //

DELIMITER ;

SELECT ProductOfNumbers(CONCAT_WS(',', quantity)) AS total_product FROM sales;

SELECT SUM(CAST(quantity AS UNSIGNED) * CAST(price AS DECIMAL(10, 2))) AS total_sales FROM sales;