Getting the value of an xml element in a CLOB

In this example, xml is stored in a CLOB, and you want to retrieve the value of a certain element:

SELECT EXTRACTVALUE(VALUE(xml), '/your/xpath/query')
INTO yourVarChar

Updating an XML element stored as a CLOB

This is the reverse of the previous example - if you want to update the value of the same XML element stored in a CLOB field:

UPDATE YourTable t 
SET t.xml_field = UPDATEXML(XMLTYPE(t.xml_field), '/your/xpath/query/text()', 'new_value').getClobVal()
WHERE = 100;