mysql pow函数

POW(X, Y)

DELIMITER $$
CREATE FUNCTION custom_pow(base DECIMAL(30, 10), exponent INT) RETURNS DECIMAL(30, 10)
DETERMINISTIC
BEGIN
    DECLARE result DECIMAL(30, 10) DEFAULT 1;
    DECLARE i INT DEFAULT 0;
    WHILE i < exponent DO
        SET result = result * base;
        SET i = i + 1;
    END WHILE;
    RETURN result;
END$$
DELIMITER ;

SELECT CASE WHEN exponent >= 0 THEN POW(base, exponent) ELSE 1 / POW(base, -exponent) END AS result
FROM your_table;

DELIMITER $$
CREATE FUNCTION custom_pow_with_negative(base DECIMAL(30, 10), exponent INT) RETURNS DECIMAL(30, 10)
DETERMINISTIC
BEGIN
    DECLARE result DECIMAL(30, 10) DEFAULT 1;
    DECLARE abs_exponent INT DEFAULT ABS(exponent);
    DECLARE i INT DEFAULT 0;
    WHILE i < abs_exponent DO
        SET result = result * base;
        SET i = i + 1;
    END WHILE;
    IF exponent < 0 THEN
        SET result = 1 / result;
    END IF;
    RETURN result;
END$$
DELIMITER ;