ATAN2 function - Amazon Redshift
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# ATAN2 function

ATAN2 is a trigonometric function that returns the arc tangent of one number divided by another number. The return value is in radians and is between `PI/2` and `-PI/2`.

## Syntax

``ATAN2(number1, number2)``

## Arguments

number1

A `DOUBLE PRECISION` number.

number2

A `DOUBLE PRECISION` number.

## Return type

`DOUBLE PRECISION`

## Examples

To return the arc tangent of `2/2` and multiply it by 4, use the following example.

``````SELECT ATAN2(2,2) * 4 AS PI;

+-------------------+
|        pi         |
+-------------------+
| 3.141592653589793 |
+-------------------+``````

To convert the arc tangent of `1/0` (which evaluates to 0) to the equivalent number of degrees, use the following example.

``````SELECT (ATAN2(1,0) * 180/(SELECT PI())) AS degrees;

+---------+
| degrees |
+---------+
|      90 |
+---------+``````