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Thanks for the explanation, I forgot that null != null in databases. I was thinking more about how null != 0 and is a separate concept in languages with optional values. You’re right that optionals in these languages don’t quite work the same as in databases

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But it's not NULL != NULL. It's that NULL == NULL is NULL. That's different! NUll != NULL is also NULL, for instance.

Maybe a concise way to describe it is that in databases NULL represents the absence of a value. Since NULL is not a value, operators like == and != don't really make sense on NULL, and also produce NULL as an output.

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