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> Reference material for ICU_NORMALIZE function

# ICU_NORMALIZE

Transliterate a string using a specified ICU transliterate ID.

## Syntax

```sql theme={"theme":{"light":"github-light","dark":"github-dark"}}
ICU_NORMALIZE(<expression>, <transliterate_id>)
```

## Parameters

| Parameter            | Description                                                              | Supported input types |
| :------------------- | :----------------------------------------------------------------------- | :-------------------- |
| `<expression>`       | An input string to transliterate.                                        | `TEXT`                |
| `<transliterate_id>` | A valid [ICU library](https://icu.unicode.org/) transliterate ID string. | `TEXT`                |

## Return Type

The `ICU_NORMALIZE` function returns a result of type `TEXT`.

## Errors

If `<transliterate_id>` is invalid, an error is thrown.

## Examples

The following example normalizes the word 'München' using the Latin-ASCII transliterate ID:

```sql theme={"theme":{"light":"github-light","dark":"github-dark"}}
SELECT icu_normalize('München', 'Latin-ASCII') normalized_word
```

| normalized\_word (TEXT) |
| :---------------------- |
| Munchen                 |

The following example applies a similar operation to the [UPPER](/reference-sql/functions-reference/string/upper) function:

```sql theme={"theme":{"light":"github-light","dark":"github-dark"}}
select ICU_NORMALIZE('AabB','Any-Upper[^xyzXYZ]') normalized_word
```

| normalized\_word (TEXT) |
| :---------------------- |
| AABB                    |

The function only works for a valid ICU transliterate ID:

```sql theme={"theme":{"light":"github-light","dark":"github-dark"}}
select ICU_NORMALIZE('','X')
```

Fails with the following error:

```
Line 1, Column 8: Unsupported locale: X
select ICU_NORMALIZE('','X')
       ^
```