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