---
title: "SET ANSI_NULLS (Transact-SQL)"
description: SET ANSI_NULLS (Transact-SQL)
author: WilliamDAssafMSFT
ms.author: wiassaf
ms.date: 04/04/2024
ms.service: sql
ms.subservice: t-sql
ms.topic: reference
f1_keywords:
  - "SET_ANSI_NULLS_TSQL"
  - "ANSI_NULLS"
  - "SET ANSI_NULLS"
  - "ANSI_NULLS_TSQL"
helpviewer_keywords:
  - "SET ANSI_NULLS statement"
  - "not equal to operator (<>)"
  - "ANSI_NULLS option"
  - "equals operator (=)"
  - "null values [SQL Server], comparison operators"
  - "comparison operators [SQL Server], null values"
dev_langs:
  - "TSQL"
monikerRange: ">=aps-pdw-2016||=azure-sqldw-latest||>=sql-server-2016||>=sql-server-linux-2017||=azuresqldb-mi-current||azuresqldb-current"
---
# SET ANSI_NULLS (Transact-SQL)
[!INCLUDE [sql-asdb-asdbmi-asa-pdw](../../includes/applies-to-version/sql-asdb-asdbmi-asa-pdw.md)]

Specifies ISO compliant behavior of the Equals (`=`) and Not Equal To (`<>`) comparison operators when they are used with null values in [!INCLUDE [ssnoversion](../../includes/ssnoversion-md.md)].

> [!NOTE]
> `SET ANSI_NULLS OFF` and the ANSI_NULLS OFF database option are deprecated. Starting with [!INCLUDE [_ss2017](../../includes/sssql17-md.md)], ANSI_NULLS is always set to ON. Deprecated features shouldn't be used in new applications. For more information, see [Deprecated Database Engine features in SQL Server 2017](../../database-engine/deprecated-database-engine-features-in-sql-server-2017.md#transact-sql-1).

:::image type="icon" source="../../includes/media/topic-link-icon.svg" border="false"::: [Transact-SQL syntax conventions](../../t-sql/language-elements/transact-sql-syntax-conventions-transact-sql.md)  

## Syntax

#### Syntax for [!INCLUDE [ssnoversion-md.md](../../includes/ssnoversion-md.md)], [!INCLUDE [sssodfull-md.md](../../includes/sssodfull-md.md)], [!INCLUDE [fabric](../../includes/fabric.md)]

```syntaxsql
SET ANSI_NULLS { ON | OFF }
```

#### Syntax for [!INCLUDE [ssazuresynapse-md.md](../../includes/ssazuresynapse-md.md)] and [!INCLUDE [sspdw-md.md](../../includes/sspdw-md.md)]

```syntaxsql
SET ANSI_NULLS ON
```

## Remarks

When ANSI_NULLS is ON, a SELECT statement that uses `WHERE column_name = NULL` returns zero rows even if there are NULL values in *column_name*. A SELECT statement that uses `WHERE column_name <> NULL` returns zero rows even if there are non-NULL values in *column_name*.  
  
When ANSI_NULLS is OFF, the Equals (`=`) and Not Equal To (`<>`) comparison operators do not follow the ISO standard. A SELECT statement that uses `WHERE column_name = NULL` returns the rows that have null values in *column_name*. A SELECT statement that uses `WHERE column_name <> NULL` returns the rows that have non-NULL values in the column. Also, a SELECT statement that uses `WHERE column_name <> XYZ_value` returns all rows that are not *XYZ_value* and that are not NULL.  
  
When ANSI_NULLS is ON, all comparisons against a null value evaluate to UNKNOWN. When SET ANSI_NULLS is OFF, comparisons of all data against a null value evaluate to TRUE if the data value is NULL. If SET ANSI_NULLS is not specified, the setting of the ANSI_NULLS option of the current database applies. For more information about the ANSI_NULLS database option, see [ALTER DATABASE (Transact-SQL)](../../t-sql/statements/alter-database-transact-sql.md).  

The following table shows how the setting of ANSI_NULLS affects the results of a number of Boolean expressions using null and non-null values.  
  
|Boolean Expression|**SET ANSI_NULLS ON**|**SET ANSI_NULLS OFF**|  
|---------------|---------------|------------|  
| `NULL = NULL` |UNKNOWN|TRUE|  
| `1 = NULL` |UNKNOWN|FALSE|  
| `NULL <> NULL` |UNKNOWN|FALSE|  
| `1 <> NULL` |UNKNOWN|TRUE|  
| `NULL > NULL` |UNKNOWN|UNKNOWN|  
| `1 > NULL` |UNKNOWN|UNKNOWN|  
| `NULL IS NULL` |TRUE|TRUE|  
| `1 IS NULL` |FALSE|FALSE|  
| `NULL IS NOT NULL` |FALSE|FALSE|  
| `1 IS NOT NULL` |TRUE|TRUE|  

SET ANSI_NULLS ON affects a comparison only if one of the operands of the comparison is either a variable that is NULL or a literal NULL. If both sides of the comparison are columns or compound expressions, the setting does not affect the comparison.  
  
For a script to work as intended, regardless of the ANSI_NULLS database option or the setting of SET ANSI_NULLS, use IS NULL and IS NOT NULL in comparisons that might contain null values.  
  
ANSI_NULLS should be set to ON for executing distributed queries.  
  
ANSI_NULLS must also be ON when you are creating or changing indexes on computed columns or indexed views. If SET ANSI_NULLS is OFF, any CREATE, UPDATE, INSERT, and DELETE statements on tables with indexes on computed columns or indexed views will fail. [!INCLUDE [ssNoVersion](../../includes/ssnoversion-md.md)] returns an error that lists all SET options that violate the required values. Also, when you execute a SELECT statement, if SET ANSI_NULLS is OFF, [!INCLUDE [ssNoVersion](../../includes/ssnoversion-md.md)] ignores the index values on computed columns or views and resolve the select operation as if there were no such indexes on the tables or views.  
  
> [!NOTE]  
> ANSI_NULLS is one of seven SET options that must be set to required values when dealing with indexes on computed columns or indexed views. The options `ANSI_PADDING`, `ANSI_WARNINGS`, `ARITHABORT`, `QUOTED_IDENTIFIER`, and `CONCAT_NULL_YIELDS_NULL` must also be set to ON, and `NUMERIC_ROUNDABORT` must be set to OFF.  
  
The [!INCLUDE [ssNoVersion](../../includes/ssnoversion-md.md)] Native Client ODBC driver and [!INCLUDE [ssNoVersion](../../includes/ssnoversion-md.md)] Native Client OLE DB Provider for [!INCLUDE [ssNoVersion](../../includes/ssnoversion-md.md)] automatically set ANSI_NULLS to ON when connecting. This setting can be configured in ODBC data sources, in ODBC connection attributes, or in OLE DB connection properties that are set in the application before connecting to an instance of [!INCLUDE [ssNoVersion](../../includes/ssnoversion-md.md)]. The default for SET ANSI_NULLS is OFF.  
  
When ANSI_DEFAULTS is ON, ANSI_NULLS is enabled.  
  
The setting of ANSI_NULLS is defined at execute or run time and not at parse time.  
  
To view the current setting for this setting, run the following query:
  
```sql  
DECLARE @ANSI_NULLS VARCHAR(3) = 'OFF';  
IF ( (32 & @@OPTIONS) = 32 ) SET @ANSI_NULLS = 'ON';  
SELECT @ANSI_NULLS AS ANSI_NULLS;   
```  
  
## Permissions
 Requires membership in the **public** role.  
  
## Examples
 The following example uses the Equals (`=`) and Not Equal To (`<>`) comparison operators to make comparisons with `NULL` and non-null values in a table. The example also shows that `IS NULL` is not affected by the `SET ANSI_NULLS` setting.  
  
```sql  
-- Create table t1 and insert values.  
CREATE TABLE dbo.t1 (a INT NULL);  
INSERT INTO dbo.t1 values (NULL),(0),(1);  
GO  
  
-- Print message and perform SELECT statements.  
PRINT 'Testing default setting';  
DECLARE @varname int;   
SET @varname = NULL;  
  
SELECT a  
FROM t1   
WHERE a = @varname;  
  
SELECT a   
FROM t1   
WHERE a <> @varname;  
  
SELECT a   
FROM t1   
WHERE a IS NULL;  
GO 
```

Now set ANSI_NULLS to ON and test.

```sql
PRINT 'Testing ANSI_NULLS ON';  
SET ANSI_NULLS ON;  
GO  
DECLARE @varname int;  
SET @varname = NULL  
  
SELECT a   
FROM t1   
WHERE a = @varname;  
  
SELECT a   
FROM t1   
WHERE a <> @varname;  
  
SELECT a   
FROM t1   
WHERE a IS NULL;  
GO  
```

Now set ANSI_NULLS to OFF and test.  

```sql
PRINT 'Testing ANSI_NULLS OFF';  
SET ANSI_NULLS OFF;  
GO  
DECLARE @varname int;  
SET @varname = NULL;  
SELECT a   
FROM t1   
WHERE a = @varname;  
  
SELECT a   
FROM t1   
WHERE a <> @varname;  
  
SELECT a   
FROM t1   
WHERE a IS NULL;  
GO  
  
-- Drop table t1.  
DROP TABLE dbo.t1;  
```  
  
## Related content

- [SET Statements (Transact-SQL)](../../t-sql/statements/set-statements-transact-sql.md)
- [SESSIONPROPERTY (Transact-SQL)](../../t-sql/functions/sessionproperty-transact-sql.md)
- [= (Equals) (Transact-SQL)](../../t-sql/language-elements/equals-transact-sql.md)
- [IF...ELSE (Transact-SQL)](../../t-sql/language-elements/if-else-transact-sql.md)
- [&#60;&#62; (Not Equal To) (Transact-SQL)](../../t-sql/language-elements/not-equal-to-transact-sql-traditional.md)
- [SET ANSI_DEFAULTS (Transact-SQL)](../../t-sql/statements/set-ansi-defaults-transact-sql.md)
- [WHERE (Transact-SQL)](../../t-sql/queries/where-transact-sql.md)
- [WHILE (Transact-SQL)](../../t-sql/language-elements/while-transact-sql.md)