# max

> 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: max
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/window-functions/max
page-component-name: cloud-data-platform
page-version: master
page-component-version: master
page-component-title: Cloud
page-relative-src-path: sql/sql-functions/window-functions/max.adoc
page-edit-url: https://github.com/redpanda-data/cloud-docs/edit/main/modules/reference/pages/sql/sql-functions/window-functions/max.adoc
description: The `max()` window function computes the maximum value of an expression across a set of rows defined by a window specification.
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/window-functions/max.md -->

The `max()` window function computes the maximum value of an expression across a set of rows defined by a window specification.

## [](#syntax)Syntax

The syntax for this function is:

```sql
MAX ([ALL] expression) OVER (
    [PARTITION BY partition_expression]
    ORDER BY sort_expression
    RANGE BETWEEN start_value AND end_value
)
```

## [](#parameters)Parameters

-   `ALL`: Retains all duplicate values from the expression.


## [](#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 text
);
INSERT INTO film(title, length, rating) VALUES
  ('ATTRACTION NEWTON', 83, 'PG-13'),
  ('CHRISTMAS MOONSHINE', 150, 'NC-17'),
  ('DANGEROUS UPTOWN', 121, 'PG'),
  ('KILL BROTHERHOOD', 54, 'G'),
  ('HALLOWEEN NUTS', 47, 'PG-13'),
  ('HOURS RAGE', 122, 'NC-17'),
  ('PIANIST OUTFIELD', 136, 'NC-17'),
  ('PICKUP DRIVING', 77, 'G'),
  ('INDEPENDENCE HOTEL', 157, 'NC-17'),
  ('PRIVATE DROP', 106, 'PG'),
  ('SAINTS BRIDE', 125, 'G'),
  ('FOREVER CANDIDATE', 131, 'NC-17'),
  ('MILLION ACE', 142, 'PG-13'),
  ('SLEEPY JAPANESE', 137, 'PG'),
  ('WRATH MILE', 176, 'NC-17'),
  ('YOUTH KICK', 179, 'NC-17'),
  ('CLOCKWORK PARADISE', 143, 'PG-13');
```

The query uses the `max()` function to find the maximum length of films for each rating category and also calculates a running maximum length as you move through the films ordered by length. The `RunningMaxLength` column updates as it encounters longer films.

```sql
SELECT
   title,
   length,
   rating,
   MAX(length) OVER ( PARTITION BY rating ) AS MaxLengthByRating,
   MAX(length) OVER (
ORDER BY
   length ROWS BETWEEN unbounded preceding AND CURRENT ROW ) AS RunningMaxLength
FROM film
ORDER BY length;
```

The query returns:

```sql
        title        | length | rating | maxlengthbyrating | runningmaxlength
---------------------+--------+--------+-------------------+------------------
 HALLOWEEN NUTS      |     47 | PG-13  |               143 |               47
 KILL BROTHERHOOD    |     54 | G      |               125 |               54
 PICKUP DRIVING      |     77 | G      |               125 |               77
 ATTRACTION NEWTON   |     83 | PG-13  |               143 |               83
 PRIVATE DROP        |    106 | PG     |               137 |              106
 DANGEROUS UPTOWN    |    121 | PG     |               137 |              121
 HOURS RAGE          |    122 | NC-17  |               179 |              122
 SAINTS BRIDE        |    125 | G      |               125 |              125
 FOREVER CANDIDATE   |    131 | NC-17  |               179 |              131
 PIANIST OUTFIELD    |    136 | NC-17  |               179 |              136
 SLEEPY JAPANESE     |    137 | PG     |               137 |              137
 MILLION ACE         |    142 | PG-13  |               143 |              142
 CLOCKWORK PARADISE  |    143 | PG-13  |               143 |              143
 CHRISTMAS MOONSHINE |    150 | NC-17  |               179 |              150
 INDEPENDENCE HOTEL  |    157 | NC-17  |               179 |              157
 WRATH MILE          |    176 | NC-17  |               179 |              176
 YOUTH KICK          |    179 | NC-17  |               179 |              179
(17 rows)
```