Re: possible bug in xpath function

Hi, I did not mensioned it but there is no difference in behavoir with relative and absolute paths. It throws error - invalid XPath statement in any case when I'm trying to use any of name(), local-name(), namespace-uri() functionse irrelative of path stated

Best regards,
Andrey

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________________________________
From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Sent: Friday, March 11, 2022 6:53:15 PM
To: Andrey Kapliev <a(dot)kapliev(at)gmail(dot)com>
Cc: pgsql-bugs(at)lists(dot)postgresql(dot)org <pgsql-bugs(at)lists(dot)postgresql(dot)org>
Subject: Re: possible bug in xpath function

Andrey Kapliev <a(dot)kapliev(at)gmail(dot)com> writes:
> It looks like XPATH name() function called from xpath() PostgreSQL
> function behave differently than when called from XMLTABLE()
> PATH.

Your examples are by no means equivalent: in particular the XMLTABLE
example is using an absolute path //* while the xpath example
is implicitly using a relative path.

> This
> behavior is different from that of 9.6 version where xpath correctly
> returns names of the nodes.

I think this was an intentional change in v11. The 11.0 release
notes mention

* Correctly handle relative path expressions in xmltable(), xpath(), and
other XML-handling functions (Markus Winand)

Per the SQL standard, relative paths start from the document node of
the XML input document, not the root node as these functions
previously did.

regards, tom lane