Question: For the product No. S18_3482 in the Order No.10108, how much discount did the customer have?
SQL: SELECT (t1.MSRP - t2.priceEach) / t1.MSRP FROM products AS t1 INNER JOIN orderdetails AS t2 ON t1.productCode = t2.productCode WHERE t1.productCode = 'S18_3482' AND t2.orderNumber = '10108'