SQL Query to select/update text from XML columns

Here's how to get data:

select * FROM
  table_with_xml w
WHERE
  w.XMLCOLUMN.EXTRACT('/xpath/goes/here/text()').getstringval() = 'test';

And how to update:

UPDATE TABLE_WITH_XML
  SET XMLCOLUMN =  UPDATEXML(XMLCOLUMN,
     '/xpath/goes/here/text()', 'a new value')
  WHERE
     xml_id = p_xml_id;