IS [NOT] NULL (Transact-SQL)
Determines whether a specified expression is NULL.
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Transact-SQL Syntax Conventions
Syntax
expression IS [ NOT ] NULL
Arguments
- expression
Is any valid expression.
- NOT
Specifies that the Boolean result be negated. The predicate reverses its return values, returning TRUE if the value is not NULL, and FALSE if the value is NULL.
Return Code Values
If the value of expression is NULL, IS NULL returns TRUE; otherwise, it returns FALSE.
If the value of expression is NULL, IS NOT NULL returns FALSE; otherwise, it returns TRUE.
Remarks
To determine whether an expression is NULL, use IS NULL or IS NOT NULL instead of comparison operators (such as = or !=). Comparison operators return UNKNOWN when either or both arguments are NULL.
Result Types
Boolean
Examples
The following example returns the name and the weight for all products for which either the weight is less than 10 pounds or the color is unknown, or NULL.
USE AdventureWorks;
GO
SELECT Name, Weight, Color
FROM Production.Product
WHERE Weight < 10.00 OR Color IS NULL
ORDER BY Name;
GO
See Also
Reference
CASE (Transact-SQL)
CREATE PROCEDURE (Transact-SQL)
CREATE TABLE (Transact-SQL)
Data Types (Transact-SQL)
Expressions (Transact-SQL)
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Operators (Transact-SQL)
Logical Operators (Transact-SQL)
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sp_help (Transact-SQL)
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