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> Fetch the complete documentation index at: https://docs.firebolt.io/llms.txt
> Use this file to discover all available pages before exploring further.

> Reference material for UPPER function

# UPPER

Converts the input string to uppercase characters. Note that Firebolt uses the `POSIX` locale, therefore `upper` only converts the ASCII characters "a" through "z" to uppercase. Non-ASCII characters remain unchanged.

## Syntax

```sql theme={"theme":{"light":"css-variables","dark":"css-variables"}}
UPPER(<expression>)
```

## Parameters

| Parameter      | Description                                         | Supported input types |
| :------------- | :-------------------------------------------------- | :-------------------- |
| `<expression>` | The string to be converted to uppercase characters. | `TEXT`                |

## Return Type

`TEXT`

## Examples

The following example converts a game player's username from lowercase to uppercase characters:

<div className="query-window">
  ```
  SELECT UPPER('esimpson') AS username;
  ```

  | username <span>text</span> |
  | :------------------------- |
  | ESIMPSON                   |

  <p><span>Rows: 1</span><span>Execution time: 6.85ms</span></p>
</div>

Because Firebolt uses the `POSIX` locale, non-ASCII characters are not uppercased:

<div className="query-window">
  ```
  SELECT UPPER('München');
  ```

  | upper <span>text</span> |
  | :---------------------- |
  | MüNCHEN                 |

  <p><span>Rows: 1</span><span>Execution time: 4.66ms</span></p>
</div>