xpath_table feature

Hello.

I've read the documentation, I think I have even found the article
after which this part of documentation has been updated
(http://markmail.org/thread/ys2a2yph5zgmnls5) but I still can't write
appropriate query :-(.

Let's consider the following:


create table test_xml (id serial primary key, xml text);

insert into test_xml (xml) values ('<?xml version="1.0" encoding="utf-8"?>                <lev1 attr1="a">
     <lev2 attr2="x" attr3="y">                        <lev3 attr4="3">                                    <lev4
attr5="aaa"></lev4>                               </lev3>                    </lev2>                    <lev2 attr2="o"
attr3="u">                       <lev3 attr4="7"></lev3>                    </lev2>                    <lev2 attr2="l"
attr3="w">                       <lev3 attr4="9">                                       <lev4 attr5="bbb"></lev4>
                        </lev3>                    </lev2>                </lev1>');
 


Please note that second /lev1/lev2/lev3 ends here and has no lev4 child node

SELECT * from xpath_table ('id',                          'xml',                          'test_xml',
         $$/lev1/lev2/@attr2|$$                          || $$/lev1/lev2/@attr3|$$                          ||
$$/lev1/lev2/lev3/lev4/@attr5$$                         ,                          'id=1') AS (
    id int,                              attr2 text,                              attr3 text,
  attr5 text                              ) ;
 

gives:
id | attr2 | attr3 | attr5
----+-------+-------+------- 1 | x     | y     | aaa 1 | o     | u     | bbb 1 | l     | w     |

I think I understand why this happens, that's because '|' in xpath
indicates a simple join and /lev1/lev2/lev3/lev4/@attr5 returns the
first matched node.

However, I'd like to have:
id | attr2 | attr3 | attr5
----+-------+-------+------- 1 | x     | y     | aaa 1 | o     | u     | 1 | l     | w     | bbb

Could you please show me the way to achieve this?

Thank you for your time

Regards,
Marcin