Categories:

Semi-structured and structured data functions (Parsing)

CHECK_XMLÂļ

Checks the validity of an XML document. If the input string is NULL or a valid XML document, the output is NULL. In case of an XML parsing error, the output string contains the error message.

See also:

PARSE_XML, TO_XML, XMLGET

SyntaxÂļ

CHECK_XML( <string_containing_xml> [ , <disable_auto_convert> ] )
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CHECK_XML( STR => <string_containing_xml>
  [ , DISABLE_AUTO_CONVERT => <disable_auto_convert> ] )
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ArgumentsÂļ

Required:

string_containing_xml . OR . STR => string_containing_xml

Specify an expression that evaluates to a VARCHAR value that contains valid XML.

Optional:

disable_auto_convert . OR . DISABLE_AUTO_CONVERT => disable_auto_convert

Specify the same value that you pass to the PARSE_XML function.

Default: FALSE

ReturnsÂļ

The data type of the returned value is VARCHAR.

Usage notesÂļ

  • You must either specify all arguments by name or by position. You can’t specify some of the arguments by name and other arguments by position.

    When specifying an argument by name, you can’t use double quotes around the argument name.

ExamplesÂļ

The following examples use the CHECK_XML function.

Show the output of the function when the XML is validÂļ

SELECT CHECK_XML('<name> Valid </name>');
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+-----------------------------------+
| CHECK_XML('<NAME> VALID </NAME>') |
|-----------------------------------|
| NULL                              |
+-----------------------------------+

Show the output of the function when the XML is invalidÂļ

SELECT CHECK_XML('<name> Invalid </WRONG_CLOSING_TAG>');
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+--------------------------------------------------+
| CHECK_XML('<NAME> INVALID </WRONG_CLOSING_TAG>') |
|--------------------------------------------------|
| no opening tag for </WRONG_CLOSING_TAG>, pos 35  |
+--------------------------------------------------+

Locate records with invalid XMLÂļ

SELECT xml_str, CHECK_XML(xml_str)
  FROM my_table
  WHERE CHECK_XML(xml_str) IS NOT NULL;
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