docs/sql-manual/sql-functions/scalar-functions/string-functions/replace-empty.md

---
{
    "title": "REPLACE_EMPTY",
    "language": "en",
    "description": "The REPLACE_EMPTY function is used to replace a part of characters in a string with other characters. Unlike the REPLACE function,"
}
---

## Description

The REPLACE_EMPTY function is used to replace a part of characters in a string with other characters. Unlike the [REPLACE](./replace.md) function, when `old` is an empty string, the `new` string is inserted before each character of the `str` string and at the end of the `str` string.

This function is mainly used to be compatible with Presto and Trino, and its behavior is exactly the same as the `REPLACE()` function in Presto and Trino. Supported since version 2.1.5.

## Syntax

```sql
REPLACE_EMPTY ( <str>, <old>, <new> )
```

## Parameters

| Parameter      | Description                                                                                                                                                                                                         |
|---------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| `<str>` | The string that needs to be replaced.                                                                                                                                                                               |
| `<old>` | The substring that needs to be replaced. If `<old>` is not in `<str>`, no replacement will be performed. If `<old>` is an empty string, the `<new>` string will be inserted before each character of the str string. |
| `<new>` | The new substring used to replace `<old>`.                                                                                                                                                                           |

## Return Value

Returns the new string after replacing the substring. Special cases:

- If any Parameter is NULL, NULL will be returned.
- If `<old>` is an empty string, the string with the `<new>` string inserted before each character of the `<str>` string will be returned.

## Examples


```sql
SELECT replace('hello world', 'world', 'universe');
```

```text
+---------------------------------------------+
| replace('hello world', 'world', 'universe') |
+---------------------------------------------+
| hello universe                              |
+---------------------------------------------+
```

```sql
SELECT replace_empty("abc", '', 'xyz');
```

```text
+---------------------------------+
| replace_empty('abc', '', 'xyz') |
+---------------------------------+
| xyzaxyzbxyzcxyz                 |
+---------------------------------+
```

```sql
SELECT replace_empty("", "", "xyz");
```

```text
+------------------------------+
| replace_empty('', '', 'xyz') |
+------------------------------+
| xyz                          |
+------------------------------+
```