> ## Documentation Index
> 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 ARRAY_TO_STRING function

# ARRAY_TO_STRING

Converts each array element to its text representation, and concatenates those using an optional delimiter. If no delimiter is provided, an empty string is used instead. `NULL` array elements are omitted.

**Alias:** `ARRAY_JOIN`

## Syntax

```sql theme={"theme":{"light":"css-variables","dark":"css-variables"}}
ARRAY_TO_STRING(<array>[, <delimiter>])
```

## Parameters

| Parameter     | Description                                             | Supported input types |
| :------------ | :------------------------------------------------------ | :-------------------- |
| `<array>`     | An array to be concatenated                             | `ARRAY`               |
| `<delimiter>` | The delimiter used for concatenating the array elements | `TEXT`                |

## Return Type

`TEXT`

## Examples

In the example below, the three elements are concatenated with no delimiter.

<div className="query-window">
  ```
  SELECT ARRAY_TO_STRING(['1', '2', '3']) AS levels;
  ```

  | levels <span>text</span> |
  | :----------------------- |
  | 123                      |

  <p><span>Rows: 1</span><span>Execution time: 8.87ms</span></p>
</div>

In this example, the levels are concatenated separated by a comma.

<div className="query-window">
  ```
  SELECT ARRAY_TO_STRING(['1', '2', '3'], ',') AS levels;
  ```

  | levels <span>text</span> |
  | :----------------------- |
  | 1,2,3                    |

  <p><span>Rows: 1</span><span>Execution time: 5.55ms</span></p>
</div>

In this example, the elements of a nested array containing a `NULL` are concatenated.

<div className="query-window">
  ```
  SELECT ARRAY_TO_STRING([[1, 2], [3, 4], [NULL, 5]], ',') AS levels;
  ```

  | levels <span>text</span> |
  | :----------------------- |
  | 1,2,3,4,5                |

  <p><span>Rows: 1</span><span>Execution time: 9.12ms</span></p>
</div>