I need to remove nodes from XML.
I try to use UpdateXML function.
For example removing node C:
SELECT UpdateXML('<A><B>b_value<C>c_value1</C></B></A>', '/A/B/C', '')
Result:
'<A><B>b_value</B></A>'
But when in XML there are multiples matches, function returns the original xml:
SELECT UpdateXML('<A><B>b_value<C>c_value1</C><C>c_value2</C></B></A>', '/A/B/C', '')
Result:
'<A><B>b_value<C>c_value1</C><C>c_value2</C></B></A>'
But I need to get such result:
'<A><B>b_value</B></A>'
How I can remove all nodes when there are multiple matches.
12.11 XML Functions :: UpdateXML
...
If no expression matching
xpath_expr
is found, or if multiple matches are found, the function returns the originalxml_target
XML fragment. ......
A possible workaround is to use a stored procedure:
DELIMITER //
CREATE PROCEDURE `sp_update_xml`(
`xml` TEXT,
`path` TEXT
)
BEGIN
DECLARE `current_item` BIGINT UNSIGNED
DEFAULT ExtractValue(`xml`,
CONCAT('COUNT(', `path`, ')')
);
WHILE `current_item` > 0 DO
SET `xml` := UpdateXML(`xml`,
CONCAT(`path`, '[', `current_item`, ']'),
''
),
`current_item` := `current_item` - 1;
END WHILE;
SELECT `xml`;
END//
DELIMITER ;
CALL `sp_update_xml`(@`xml`, '/A/B/C');
See db-fiddle.