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NULL means exactly “we don’t know”. That’s the beauty of the NULL concept. So we will never know if anything is equal or unequal to “I don’t know”. Even comparing NULL with NULL. The Boolean retu...
#1: Initial revision
by
marcothesane
·
2026-01-19T16:59:02Z (8 months ago)
NULL means exactly “we don’t know”. That’s the beauty of the NULL concept. So we will never know if anything is equal or unequal to “I don’t know”. Even comparing NULL with NULL. The Boolean returned by such a comparison will be “we don’t know”, too. It won’t satisfy the WHERE condition. Hence, as said, IS [NOT] NULL needs to be the predicate.