# STD_DEV

Calculates the population standard deviation of a numeric field.

## Syntax

`STD_DEV(number)`

### Parameters

#### number

The numeric column or expression for which to calculate the population standard deviation.

## Examples

Calculates the population standard deviation of the height field for all employees.

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

Calculates the population standard deviation of the maximum salary change for each employee.

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