# NVL and IFNULL

Checks if an expression evaluates to `NULL`, and if so, evaluates a replacement expression and returns its value.

The `NVL` and `IFNULL` functions are synonyms. The following discussion of `NVL` applies to `IFNULL`, as both work identically.

## Syntax

```
NVL ( expression_to_check, expression_if_null )

```

## Arguments

**expression\_to\_check**

An expression that evaluates to a value of any data type. `NVL` checks if this value is `NULL`, and if so, evaluates `expression_if_null` and returns the result.

**expression\_if\_null**

An expression that evaluates to a value of any data type. `NVL` returns this value if `expression_to_check` is `NULL`.

## Remarks

If `expression_to_check` and `expression_if_null` have different data types, then `NVL` casts its return value as follows:

* If `expression_to_check` contains character data, `NVL` casts its return value to `VARCHAR`.
* if `expression_to_check` is numeric, `NVL` casts its return value to the data type of the expression (`expression_to_check` or `expression_if_null`) that has the higher numeric precision.

## Examples

The following example demonstrates the simplest case of calling `NVL`.

```sql
SELECT NVL(NULL, 'NULL value') AS 'result';

```

```output

+------------+
| result     |
+------------+
| NULL value |
+------------+

```

The following example shows how to call `NVL` once per table row.

```sql
DROP DATABASE IF EXISTS singlestore_docs_example;
CREATE DATABASE singlestore_docs_example;
use singlestore_docs_example;
CREATE TABLE person(name VARCHAR(80), state VARCHAR(40));
INSERT INTO person VALUES ('John Jones', 'New York'), ('Mary Smith', NULL),
    ('Ann Brown', NULL);
SELECT name, NVL(state, 'Unknown') AS state FROM person
ORDER BY name;


```

```output

+------------+----------+
| name       | state    |
+------------+----------+
| Ann Brown  | Unknown  |
| John Jones | New York |
| Mary Smith | Unknown  |
+------------+----------+

```

***

Modified at: February 24, 2023

Source: [/db/v9.1/reference/sql-reference/conditional-functions/nvl-and-ifnull/](https://docs.singlestore.com/db/v9.1/reference/sql-reference/conditional-functions/nvl-and-ifnull/)

(An index of the documentation is available at /llms.txt)