How much is the discount applied to the order with the highest unit price?
highest unit price refers to Max(Unit Price)
SELECT `Discount Applied` FROM `Sales Orders` WHERE REPLACE(`Unit Price`, ',', '') = ( SELECT REPLACE(`Unit Price`, ',', '') FROM `Sales Orders` ORDER BY REPLACE(`Unit Price`, ',', '') DESC LIMIT 1 ) ORDER BY REPLACE(`Unit Price`, ',', '') DESC LIMIT 1