﻿---
title: ES|QL SUBSTRING function
description: 
url: https://www.elastic.co/elastic/docs-builder/docs/2842/reference/query-languages/esql/functions-operators/string-functions/substring
products:
  - Elasticsearch
---

# ES|QL SUBSTRING function
## Syntax

![Embedded](https://www.elastic.co/elastic/docs-builder/docs/2842/reference/query-languages/esql/images/functions/substring.svg)


## Parameters

<definitions>
  <definition term="string">
    String expression. If `null`, the function returns `null`.
  </definition>
  <definition term="start">
    Start position.
  </definition>
  <definition term="length">
    Length of the substring from the start position. Optional; if omitted, all positions after `start` are returned.
  </definition>
</definitions>


## Description

Returns a substring of a string, specified by a start position and an optional length.

## Supported types


| string  | start   | length  | result  |
|---------|---------|---------|---------|
| keyword | integer | integer | keyword |
| text    | integer | integer | keyword |


## Examples

This example returns the first three characters of every last name:
```esql
FROM employees
| KEEP last_name
| EVAL ln_sub = SUBSTRING(last_name, 1, 3)
```


| last_name:keyword | ln_sub:keyword |
|-------------------|----------------|
| Awdeh             | Awd            |
| Azuma             | Azu            |
| Baek              | Bae            |
| Bamford           | Bam            |
| Bernatsky         | Ber            |

A negative start position is interpreted as being relative to the end of the string.
This example returns the last three characters of every last name:
```esql
FROM employees
| KEEP last_name
| EVAL ln_sub = SUBSTRING(last_name, -3, 3)
```


| last_name:keyword | ln_sub:keyword |
|-------------------|----------------|
| Awdeh             | deh            |
| Azuma             | uma            |
| Baek              | aek            |
| Bamford           | ord            |
| Bernatsky         | sky            |

If length is omitted, substring returns the remainder of the string.
This example returns all characters except for the first:
```esql
FROM employees
| KEEP last_name
| EVAL ln_sub = SUBSTRING(last_name, 2)
```


| last_name:keyword | ln_sub:keyword |
|-------------------|----------------|
| Awdeh             | wdeh           |
| Azuma             | zuma           |
| Baek              | aek            |
| Bamford           | amford         |
| Bernatsky         | ernatsky       |