> ## 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 DECODE function

# DECODE

Decode binary data from a SQL expression of type `TEXT`.

## Syntax

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

## Parameters

| Parameter      | Description                         | Supported input types                        |
| :------------- | :---------------------------------- | :------------------------------------------- |
| `<expression>` | A SQL expression of type `TEXT`     | `TEXT`                                       |
| `<format>`     | Format to use to decode binary data | `HEX`, `ESCAPE`, `BASE64` (case insensitive) |

The `HEX` format represents each 4 bits of data as one hexadecimal digit, 0 through f, writing the higher-order digit of each byte first. The `DECODE` function accepts the a-f characters in either upper or lower case. An error is raised when `DECODE` is given invalid hex data — including when given an odd number of characters.

The `ESCAPE` format converts zero bytes and bytes with the high bit set into octal escape sequences (\nnn) and doubles backslashes. Other byte values are represented literally. The `DECODE` function will raise an error if a backslash is not followed by either a second backslash or three octal digits; it accepts other byte values unchanged.

THE `BASE64` format, per [RFC 2045 Section 6.8](https://www.rfc-editor.org/rfc/rfc2045#section-6.8), breaks encoded lines at 76 characters using a newline for end of line. The `DECODE` function ignores carriage-return, newline, space, and tab characters. Otherwise, an error is raised when `DECODE`is supplied invalid base64 data — including when trailing padding is incorrect.

## Return type

`BYTEA`

## Example

The following examples decode expressions from the `HEX`, `ESCAPE`, and `BASE64` format:

```sql theme={"theme":{"light":"github-light","dark":"github-dark"}}
SELECT
	DECODE('31323300343536', 'HEX');
```

**Returns**: `\x31323300343536`

```sql theme={"theme":{"light":"github-light","dark":"github-dark"}}
SELECT
	DECODE('123\000456', 'ESCAPE');
```

**Returns**: `\x31323300343536`

```sql theme={"theme":{"light":"github-light","dark":"github-dark"}}
SELECT
	DECODE('MTIzADQ1Ng==', 'BASE64');
```

**Returns**: `\x31323300343536`