ISNULL

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Syntax

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Scalar

isnull(value)

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Arguments

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Returns

• Type: BOOLEAN
• Possible values: TRUE or FALSE.
• NULL behavior: Returns TRUE for NULL and FALSE for non-NULL input; the result itself is not NULL.

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Properties

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Usage notes

• This is a one-argument Boolean test, not the two-argument replacement function named ISNULL in some other engines.
• INTEGER and INT mean the same type; STRING means VARCHAR text. NULL can be used with a supported type. Cast NULL explicitly when its type would otherwise be unclear.
• Deterministic: The same inputs and settings produce the same result.

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Examples

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Typical behavior

SELECT isnull(CAST(NULL AS INT)) AS null_value, isnull(1) AS present;

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An empty string is not NULL

SELECT isnull('') AS empty_string, isnull(CAST(NULL AS VARCHAR)) AS null_string;

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Related functions

• nvl