I’m not sure what to say here. ... Yes? If you’re referring to the Oracle behaviour where '' IS NULL, well, the rude way of putting it is that Oracle is doing a stupid. The more polite way of putting it is that Oracle is absolutely ancient and these parts probably existed long before people had the theory developed well enough to recognize which things make sense and which don’t, and now Oracle’s backward-compat-driven livelihood depends on not recognizing that it’s making no sense there. Either way, if this matters to you, you’re stuck and will have to work around this particular wart.