# ATAN

> Calculate the arc tangent (inverse tangent) of a number, returning an angle in radians using SQL in StackQL.

Source: https://stackql.io/language-spec/functions/math/trigonometric/atan

Calculates the arc tangent (inverse tangent) of a number, which is the angle in radians whose tangent is the specified number.

See also:  
[[`SELECT`]](/language-spec/select)

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## Syntax

```sql
SELECT ATAN(value) FROM <multipartIdentifier>;
```

## Arguments

__*value*__  
A numeric expression for which the arc tangent is to be calculated.

## Return Value(s)
Returns the arc tangent of the specified value in radians.

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## Examples

### Calculate the arc tangent of 1

```sql
SELECT ATAN(1) AS arc_tangent_value;
```

This query returns π/4 or approximately `0.785`, as the arc tangent of 1 is π/4 radians.

### Calculate the arc tangent of 0

```sql
SELECT ATAN(0) AS arc_tangent_value;
```

This query calculates the arc tangent of 0, resulting in `0`, since the tangent of 0 radians is 0.