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    MaxCompute:FROM_CHARSET

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    MaxCompute:FROM_CHARSET

    Last Updated:Apr 01, 2024

    Converts binary data that is in the specified encoding format into a UTF-8 encoded string for subsequent calculation. This topic describes the syntax and parameters of the FROM_CHARSET function and provides examples on how to use this function.

    Syntax

    STRING FROM_CHARSET(binary <source>, string <source_charset>, [string <mode>])

    Parameters

    • source: required. A value of the BINARY type. This parameter specifies the binary data that you want to convert.

    • source_charset: required. A value of the STRING type. This parameter specifies the original encoding format of the binary data that is specified by source. Valid values: UTF-8, UTF-16, UTF-16LE, UTF-16BE, ISO-8859-1, US-ASCII, GB2312, GBK, and GB18030.

    • mode: optional. A value of the STRING type. This parameter specifies the processing mode if a character cannot be converted when the FROM_CHARSET function converts the binary data specified by source into a string in the specified encoding format. Valid values:

      • NONE: reports an error. No processing is performed. This is the default value.

      • TRANSLIT: replaces the character with a similar character in the specified encoding format.

      • IGNORE: ignores the error and continues to run the command.

    Return value

    A value of the STRING type in the UTF-8 encoding format is returned. If an input parameter is null or an empty string, the return value varies based on the following rules:

    • If an input parameter is null, null is returned.

    • If an input parameter is an empty string, an error is returned.

    Examples

    • Example 1: Convert UTF-8 encoded binary data into a UTF-8 encoded string. 

      SELECT FROM_CHARSET(unhex('e58aa0e6b2b9e9949fe696a4e68bb70a'),'UTF-8', 'TRANSLIT');

      The following result is returned:

      +------------+
| _c0        |
+------------+
| 加油锟斤拷
     |
+------------+

    • Example 2: Convert GBK-encoded binary data into a UTF-8 encoded string. 

      SELECT FROM_CHARSET(unhex('b9feb9febac3a4ce'), 'GBK');

      The following result is returned: 

      +------------+
| _c0        |
+------------+
| 哈哈好の       |
+------------+

    • Example 3: If an input parameter is null, null is returned. 

      SELECT FROM_CHARSET(unhex('b9feb9febac3a4ce'), null);

      The following result is returned: 

      +------------+
| _c0        |
+------------+
| NULL       |
+------------+
    Note

    The UNHEX function returns a string that is represented by a hexadecimal string. For more information, see UNHEX.

    References