Amazon Redshift will no longer support the use of Python UDFs after June 30, 2026. We will start enforcing it in phases. For more information on the details of Python end of life and migration options, see the [ blog post ](https://aws.amazon.com/blogs/big-data/amazon-redshift-python-user-defined-functions-will-reach-end-of-support-after-june-30-2026/) that was published on June 30, 2025. 

# ATAN function
<a name="r_ATAN"></a>

ATAN is a trigonometric function that returns the arc tangent of a number. The return value is in radians and is between `-PI` and `PI`.

## Syntax
<a name="r_ATAN-synopsis"></a>

```
ATAN(number)
```

## Arguments
<a name="r_ATAN-argument"></a>

 *number*   
The input parameter is a `DOUBLE PRECISION` number. 

## Return type
<a name="r_ATAN-return-type"></a>

`DOUBLE PRECISION`

## Examples
<a name="r_ATAN-examples"></a>

To return the arc tangent of `1` and multiply it by 4, use the following example.

```
SELECT ATAN(1) * 4 AS pi;
            
+-------------------+
|        pi         |
+-------------------+
| 3.141592653589793 |
+-------------------+
```

To convert the arc tangent of `1` to the equivalent number of degrees, use the following example. 

```
SELECT (ATAN(1) * 180/(SELECT PI())) AS degrees;

+---------+
| degrees |
+---------+
|      45 |
+---------+
```