# stddev

> For the complete documentation index, see [llms.txt](https://docs.redpanda.com/llms.txt). Component-specific: [cloud-data-platform-full.txt](https://docs.redpanda.com/cloud-data-platform-full.txt)

---
title: stddev
latest-operator-version: v26.1.4
latest-console-tag: v3.7.3
latest-connect-version: 4.93.0
latest-redpanda-tag: v26.1.9
docname: sql/sql-functions/aggregate-functions/statistics/stddev
page-component-name: cloud-data-platform
page-version: master
page-component-version: master
page-component-title: Cloud
page-relative-src-path: sql/sql-functions/aggregate-functions/statistics/stddev.adoc
page-edit-url: https://github.com/redpanda-data/cloud-docs/edit/main/modules/reference/pages/sql/sql-functions/aggregate-functions/statistics/stddev.adoc
description: The `stddev()` aggregate function calculates the sample standard deviation of a set of numeric values.
page-topic-type: reference
page-git-created-date: "2026-05-26"
page-git-modified-date: "2026-05-26"
---

<!-- Source: https://docs.redpanda.com/cloud-data-platform/reference/sql/sql-functions/aggregate-functions/statistics/stddev.md -->

The `stddev()` aggregate function calculates the sample standard deviation of a set of numeric values. Standard deviation measures the dispersion or spread of data points around the mean.

## [](#syntax)Syntax

The syntax for this function is:

```sql
STDDEV(expression)
```

## [](#parameters)Parameters

-   `expression`: Numeric expression or column.


## [](#examples)Examples

The following example uses a simplified version of the `film` table from the Pagila database, containing only the `title`, `length` and `rating` columns. The complete schema for the `film` table can be found on the [Pagila](https://www.postgresql.org/ftp/projects/pgFoundry/dbsamples/pagila/pagila/) database website.

```sql
DROP TABLE IF EXISTS film;
CREATE TABLE film (
  title text NOT NULL,
  length int,
  rating int
);
INSERT INTO film(title, length, rating) VALUES
  ('ATTRACTION NEWTON', 83, 5),
  ('CHRISTMAS MOONSHINE', 150, 7),
  ('DANGEROUS UPTOWN', 121, 4),
  ('KILL BROTHERHOOD', 54, 3),
  ('HALLOWEEN NUTS', 47, 5),
  ('HOURS RAGE', 122, 7),
  ('PIANIST OUTFIELD', 136, 7),
  ('PICKUP DRIVING', 77, 3),
  ('INDEPENDENCE HOTEL', 157, 7),
  ('PRIVATE DROP', 106, 4),
  ('SAINTS BRIDE', 125, 3),
  ('FOREVER CANDIDATE', 131, 7),
  ('MILLION ACE', 142, 5),
  ('SLEEPY JAPANESE', 137, 4),
  ('WRATH MILE', 176, 7),
  ('YOUTH KICK', 179, 7),
  ('CLOCKWORK PARADISE', 143, 5);
```

The following query uses the `stddev()` function to calculate the sample standard deviation for the `length` column:

```sql
SELECT
    STDDEV(length) AS LengthStdDev
FROM film;
```

The query returns:

```sql
   lengthstddev
-------------------
 38.38092740197003
(1 row)
```