Shane O’Neill shows a subtle difference between ISNULL and COALESCE:
You may be asking yourself “What the…?!”.
I asked myself the same question but then I thought of a better idea and asked my Senior the question instead (he usually has better answers than I do), who proceeded to tell me that the final test would only work exactly at midnight!
….so I repeated my question to him.
It’s an interesting read, and not something you’d commonly think about.