How to extract xml comments

Question

Hi,
I have loaded XML files into my table of XML Type . I have comments in XML file. This comments are important to us and I want to extract this comments . How can we extract the comments present in XML file. I was not able to find any function which can do it.
Thanks,
Ramesh.

Answer 1

Hi Ramesh,
First of all, instead of posting three times in different forums, why not provide relevant details such as database version and a sample XML?
Generally, XML comments are not meant to be extracted.
If they contain so important data then most likely that data should be stored in regular element or attribute nodes.
Here's an example using XQuery though :
SQL> create table tmp_xml of xmltype;
Table created
SQL>
SQL> insert into tmp_xml values (
  2   xmltype('<root>
  3  <!-- this is a comment -->
  4  <item/>
  5  <!-- this is another comment -->
  6  </root>')
  7  );
1 row inserted
SQL>
SQL> select x.comment_text
  2  from tmp_xml t
  3     , xmltable(
  4         '/descendant::comment()'
  5         passing t.object_value
  6         columns comment_text varchar2(200) path '.'
  7       ) x
  8  ;
COMMENT_TEXT
this is a comment
this is another comment