Which operator treats two NULLs as matching?

Question

Accepted Answer

IS NOT DISTINCT FROM is a NULL-safe equality operator that uses two-valued logic (only TRUE or FALSE, never UNKNOWN). It returns TRUE when both sides are equal OR both sides are NULL. This is the correct tool when you need a JOIN or WHERE that treats two NULLs as matching. The standard `=` operator returns UNKNOWN for NULL = NULL, so those rows would be excluded.