# STD_DEV

The STD_DEV function calculates the standard deviation of a numeric field.

## Syntax

`STD_DEV(number)`

### Parameters

#### number

A numeric field for which the standard deviation is calculated.

## Examples

This example calculates the standard deviation of the 'height' column:

```esql
FROM employees
| STATS STD_DEV(height)
```

In this example, we first calculate the maximum salary change for each employee using the `MV_MAX` function. The `STD_DEV` function is then used to calculate the standard deviation of these maximum salary changes:

```esql
FROM employees
| STATS std_dev_salary_change = STD_DEV(MV_MAX(salary_change))
```
