# NULLIF

## Syntax

```sql
NULLIF(expr1,expr2)
```

## Description

Returns `NULL` if expr1 = expr2 is true, otherwise returns expr1. This is the same as [CASE](https://mariadb.com/docs/server/reference/sql-functions/control-flow-functions/case-operator) `WHEN` expr1 = expr2 `THEN NULL ELSE` expr1 `END`.

## Examples

```sql
SELECT NULLIF(1,1);
+-------------+
| NULLIF(1,1) |
+-------------+
|        NULL |
+-------------+

SELECT NULLIF(1,2);
+-------------+
| NULLIF(1,2) |
+-------------+
|           1 |
+-------------+
```

## See Also

* [NULL values](https://mariadb.com/docs/server/reference/data-types/null-values)
* [IS NULL operator](https://mariadb.com/docs/server/reference/sql-structure/operators/comparison-operators/is-null)
* [IS NOT NULL operator](https://mariadb.com/docs/server/reference/sql-structure/operators/comparison-operators/is-not-null)
* [COALESCE function](https://mariadb.com/docs/server/reference/sql-structure/operators/comparison-operators/coalesce)
* [IFNULL function](https://mariadb.com/docs/server/reference/sql-functions/control-flow-functions/ifnull)
* [CONNECT data types](https://mariadb.com/docs/server/server-usage/storage-engines/connect/connect-data-types#null-handling)

<sub>*This page is licensed: GPLv2, originally from*</sub> [<sub>*fill\_help\_tables.sql*</sub>](https://github.com/MariaDB/server/blob/main/scripts/fill_help_tables.sql)

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