IS NULL (Transact-SQL)
Applies to:
SQL Server
Azure SQL Database
Azure SQL Managed Instance
Azure Synapse Analytics
Analytics Platform System (PDW)
SQL analytics endpoint in Microsoft Fabric
Warehouse in Microsoft Fabric
Determines whether a specified expression is NULL.
Transact-SQL syntax conventions
Syntax
expression IS [ NOT ] NULL
Note
To view Transact-SQL syntax for SQL Server 2014 (12.x) and earlier versions, see Previous versions documentation.
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.
Result Types
Boolean
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.
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 AdventureWorks2022;
GO
SELECT Name, Weight, Color
FROM Production.Product
WHERE Weight < 10.00 OR Color IS NULL
ORDER BY Name;
GO
Examples: Azure Synapse Analytics and Analytics Platform System (PDW)
The following example returns the full names of all employees with middle initials.
-- Uses AdventureWorks
SELECT FirstName, LastName, MiddleName
FROM DIMEmployee
WHERE MiddleName IS NOT NULL
ORDER BY LastName DESC;
See Also
CASE (Transact-SQL)
CREATE PROCEDURE (Transact-SQL)
CREATE TABLE (Transact-SQL)
Data Types (Transact-SQL)
Expressions (Transact-SQL)
INSERT (Transact-SQL)
LIKE (Transact-SQL)
Operators (Transact-SQL)
Logical Operators (Transact-SQL)
SELECT (Transact-SQL)
sp_help (Transact-SQL)
UPDATE (Transact-SQL)
WHERE (Transact-SQL)