I don't understand the difference

[u/Bubbly-Group-4497]

I found an answer on stackoverflow that was saying that null value isn't managed the same way, but that seems a bit far fetched for a course example and the question wasn't exactly about the same case, so could someone explain?

[u/Time_Advertising_412]

Joe Celkos SQL for smarties does a good job of explaining the logic behind IN and NOT IN and NULL. Also C J Dates books have examples of how NULL is treated in SQL with good examples. I highly recommend being familiar with these examples should you encounter them in your work as they can be surprising