Operations on XML-formatted data in Oracle, CLOB type conversion xmltype type

Today there is a problem with the operation of XML format data in Oracle.
Problem record: The requirement is clear that the field type is XmlType, to do is to resolve the field, but because of the database designer's problem, some tables in the field type is designed as CLOB type.
Workaround:
XmlType type parsing is easy: using the Extractvalue function, you can use:

select column_name1,column_name2,extractvalue(column_name3,‘/nodeName1/nodeName2/nodeName3‘) from table;

The CLOB type resolves first through the XmlType conversion, using:

select column_name1,column_name2,extractvalue(xmltype(column_name3),‘/nodeName1/nodeName2/nodeName3‘) from table;

The person who designs the table under this contempt does not look closely at the design document.

Operations on XML-formatted data in Oracle, CLOB type conversion xmltype type