ALTER TABLE `products`
    ADD COLUMN `warranty_year` TINYINT UNSIGNED NOT NULL DEFAULT 0 AFTER `unit_id`,
    ADD COLUMN `warranty_month` TINYINT UNSIGNED NOT NULL DEFAULT 0 AFTER `warranty_year`;
    
ALTER TABLE `product_to_store`
    ADD COLUMN `dealer_price` DECIMAL(25,4) NOT NULL DEFAULT 0.0000 AFTER `sell_price`;


ALTER TABLE `customers`
	ADD COLUMN `customer_code` INT(10) UNSIGNED NULL DEFAULT NULL AFTER `customer_id`,
	ADD UNIQUE INDEX `customer_code` (`customer_code`);