> ## Documentation Index
> Fetch the complete documentation index at: https://docs.e6data.com/llms.txt
> Use this file to discover all available pages before exploring further.

# ISNAN

> Tests whether a numeric value is NaN.

<div className="e6-meta"><span className="e6-eyebrow e6-eyebrow--quiet">Scalar function</span></div>

Returns NULL when an argument is NULL.

## Syntax

### Scalar

```sql theme={"theme":{"light":"github-light","dark":"github-dark"}}
isnan(value)
```

## Arguments

| Name | Type | Required | Description |
| - | - | - | - |
| value | TINYINT, SMALLINT, INTEGER, BIGINT, FLOAT, DOUBLE or DECIMAL(p, s) | Yes | The numeric expression to inspect. For DECIMAL(p, s), p is precision (total digits) and s is scale (digits after the decimal point). |

## Returns

* Type: BOOLEAN
* Possible values: TRUE for floating-point NaN; FALSE for other non-NULL numeric values.
* NULL behavior: Returns NULL when an argument is NULL.

## Properties

| Property | Value |
| - | - |
| Deterministic | Yes |
| Supports window usage | No |
| Exact result | Yes |

## Usage notes

* Integer and decimal values are never NaN.
* INTEGER and INT mean the same type; STRING means VARCHAR text. NULL can be used with a supported type. Cast NULL explicitly when its type would otherwise be unclear.

## Examples

### Value and NULL input

```sql theme={"theme":{"light":"github-light","dark":"github-dark"}}
SELECT isnan(CAST(1 AS DOUBLE)) AS "value", isnan(CAST(NULL AS DOUBLE)) AS null_value;
```

| value | null\_value |
| - | - |
| false | NULL |

### NaN and ordinary numbers

```sql theme={"theme":{"light":"github-light","dark":"github-dark"}}
SELECT isnan(CAST('NaN' AS DOUBLE)) AS not_a_number, isnan(CAST(2.5 AS DOUBLE)) AS ordinary_number;
```

| not\_a\_number | ordinary\_number |
| - | - |
| true | false |


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