Decodes a URL-encoded string in application/x-www-form-urlencoded MIME format into a standard string.
Limits
Supported only in Realtime Compute for Apache Flink that uses Ververica Runtime (VVR) 8.0.8 or later.
Syntax
VARCHAR URL_DECODE(VARCHAR input)
VARCHAR URL_DECODE(VARCHAR input, VARCHAR encoding)Parameters
| Parameter | Data type | Description |
|---|---|---|
input |
VARCHAR | The URL-encoded input string. |
encoding |
VARCHAR | The character encoding used for decoding, such as GBK or UTF-8. Defaults to UTF-8. Optional. |
If input contains invalid percent-encoding sequences, decoding fails and NULL is returned. The encoding specified must match the encoding used when the string was originally encoded, otherwise the output may be garbled or parsing may fail.
Examples
Example 1: Default UTF-8 decoding
Input data (T1)
| id | input (VARCHAR) |
|---|---|
| 1 | http://calcite.apache.org |
| 2 | https%3A%2F%2Fcalcite.apache.org |
| 3 | http%3A%2F%2Ftest%3Fa%3Db%26c%3Dd |
| 4 | http%3A%2F%2F%E4%BD%A0%E5%A5%BD |
| 5 | test |
| 6 | https%%3A%2F%2Fcalcite.apache.org |
Test statement
SELECT
id,
URL_DECODE(input) AS `value`
FROM
T1;Result
| id (INT) | value (VARCHAR) |
|---|---|
| 1 | http://calcite.apache.org |
| 2 | https://calcite.apache.org |
| 3 | http://test?a=b&c=d |
| 4 | http://Hello |
| 5 | test |
| 6 | NULL |
Row 1 returns the input unchanged because it is not URL-encoded. Row 6 returns NULL because %% is an invalid percent-encoding sequence.
Example 2: Decoding with a specified character encoding
Input data (T2)
| id (INT) | input (VARCHAR) | encoding (VARCHAR) |
|---|---|---|
| 1 | https%3A%2F%2Fcalcite.apache.org% |
UTF-8 |
| 2 | https%3A%2F%2Fcalcite.apache.org |
gb2312 |
Test statement
SELECT
id,
URL_DECODE(input, encoding) AS `value`
FROM
T2;Result
| id (INT) | value (VARCHAR) |
|---|---|
| 1 | NULL |
| 2 | http://Hello |
Row 1 returns NULL because the trailing % is an incomplete percent-encoding sequence.