is not distinct from
The not standardized binary is
operator works in some SQL dialects like a null
-safe comparison: It is similar to =
but never returns unknown. Instead it returns false if only one argument is null
or true if both arguments are null
.
SELECT …
FROM …
WHERE c1 is c2
Note that this is not the same as the standardized unary is [not] null
operator as it allows two arbitrary expressions to be compared.
Standardised version of this operator: IS NOT DISTINCT FROM
(null-safe equals comparison)
Tutorials:
<=>
is not defined in the SQL standard.
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