Are 'sweet' and 'mild' - Italian Sausage - the same thing? Do they refer to the same kind? Or is there a subtle difference?

And what essentially encapsulates the concept of a sausage being sweet? Is it typical sucrose driven sweetness inherent to the product...or the resultant chemical aftertaste on consuming it?

Cooking geeks unite! We have a problem.
Both sweet and mild refers to the sausages without hot red pepper flakes. The fact they are called sweet Italian sausages doesn't mean they contain sugar.