---
title: ES|QL TO_LOWER function
description: 
url: https://www.elastic.co/elastic/docs-builder/docs/3028/reference/query-languages/esql/functions-operators/string-functions/to_lower
products:
  - Elasticsearch
---

# ES|QL TO_LOWER function
## Syntax

![Embedded](https://www.elastic.co/elastic/docs-builder/docs/3028/reference/query-languages/esql/images/functions/to_lower.svg)


## Parameters

<definitions>
  <definition term="str">
    String expression. If `null`, the function returns `null`. The input can be a single-valued column or expression, or a multi-valued column or expression <applies-to>Elastic Stack: Generally available since 9.1</applies-to>.
  </definition>
</definitions>


## Description

Returns a new string representing the input string converted to lower case.

## Supported types


| str     | result  |
|---------|---------|
| keyword | keyword |
| text    | keyword |


## Examples

```esql
ROW message = "Some Text"
| EVAL message_lower = TO_LOWER(message)
```


| message:keyword | message_lower:keyword |
|-----------------|-----------------------|
| Some Text       | some text             |

<applies-to>
  - Elastic Stack: Generally available since 9.1
</applies-to>

```esql
ROW v = TO_LOWER(["Some", "Text"])
```


| v:keyword        |
|------------------|
| ["some", "text"] |