I’d start by ensuring the universe doesn’t implode over a zero or negative list price—so, my first condition would be record.list_price > 0. After all, I'm not in the business of selling products with prices less than or equal to zero (unless we’ve entered some alternate dimension of reverse economics). Plus, dividing by zero isn’t just bad math; it’s a straight-up party pooper for your database. So, let’s keep things sensible and error-free!

And I guess sometimes you can sell product without any inventory which may result in standard price of 0 and the margin of 100%.