Trigger that validates line item amounts when updating a table in MySql - mysql

Question

I am working on a lab for school which states: "Create a trigger named products_before_update that checks the new value for the discount_percent column of the Products table. This trigger should raise an appropriate error if the discount percent is greater than 100 or less than 0.
If the new discount percent is between 0 and 1, this trigger should modify the new discount percent by multiplying it by 100. That way, a discount percent of .2 becomes 20.
Test this trigger with an appropriate UPDATE statement."
My script updates the discount percent column successfully, however the "If, Then" portion does not seem to be accomplishing anything. IF I input a discount percent over 100, it does not show any errors and simply updates it. Same issue if my discount percent is less than zero. Also, if I input a number from 0-1 then it is not multiplying it by 10. Any advise would be greatly appreciated!
Here is my code:
USE my_guitar_shop;
DROP TRIGGER IF EXISTS products_before_update;
DELIMITER //
CREATE TRIGGER products_before_update
BEFORE UPDATE ON Products
FOR EACH ROW
BEGIN
DECLARE discount_percent_amount INT;
SELECT discount_percent
INTO discount_percent_amount
FROM Products
WHERE product_id = NEW.product_id;
IF discount_percent_amount > 100 THEN
SIGNAL SQLSTATE 'HY000'
set message_text =
'the discount percent cannot be greater than 100';
ELSEIF discount_percent_amount < 0 THEN
SIGNAL SQLSTATE 'HY000'
set message_text =
'the discount percent cannot be less than 0';
ELSEIF discount_percent_amount < 1 THEN
SET discount_percent_amount = (discount_percent * 10);
END IF;
END//
DELIMITER ;
UPDATE Products
SET discount_percent = .4
WHERE product_id = 3;
SELECT * FROM products;

Answer 1

I ended up getting it, thanks for your tip....
USE my_guitar_shop;
DROP TRIGGER IF EXISTS products_before_update;
DELIMITER //
CREATE TRIGGER products_before_update
BEFORE UPDATE ON Products
FOR EACH ROW
BEGIN
IF NEW.discount_percent > 100 THEN
SIGNAL SQLSTATE 'HY000'
set message_text =
'the discount percent cannot be greater than 100';
ELSEIF new.discount_percent < 0 THEN
SIGNAL SQLSTATE 'HY000'
set message_text =
'the discount percent cannot be less than 0';
ELSEIF NEW.discount_percent < 1 THEN
SET NEW.discount_percent = (NEW.discount_percent * 100);
END IF;
END//
DELIMITER ;
UPDATE Products
SET discount_percent = .4
WHERE product_id = 3;