MySQL Bugs: #22823: gt and lt operators appear to be reversed in ExtractValue() command

Bug #22823	gt and lt operators appear to be reversed in ExtractValue() command
Submitted:	29 Sep 2006 15:04	Modified:	17 Nov 2006 17:20
Reporter:	Vincent Fumo
Status:	Closed
Category:	Server: XML	Severity:	S2 (Serious)
Version:	5.1.11	OS:	Microsoft Windows (Windows)
Assigned to:	Alexander Barkov	Target Version:
Tags:	XML, XPath, ExtractValue

Description:
In reguards to XPath evaluation of integer and floating point values, the greater than and
less than operators appear to have been implemented in reverse.

How to repeat:
If you run the following select statement:

SELECT
ExtractValue(
'<entry><id>foo</id><pt>10</pt></entry><entry><id>bar</id><pt>50</pt></entry>',
'/entry[(pt < 9)]/id'
);

the result you get is: 'foo bar' where you would expect to get 0 results. If you reverse
the '<' operator as follows:

SELECT
ExtractValue(
'<entry><id>foo</id><pt>10</pt></entry><entry><id>bar</id><pt>50</pt></entry>',
'/entry[(pt > 9)]/id'
);

you get 0 results.

This can be repeated using floating points as well.

Suggested fix:
Reverse the implementation of the operarors when they are used to evaluate integers and
floating point values.

mysqltest test case

Attachment: bug22823.tar.gz (application/x-gzip, text), 786 bytes.

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/14159

ChangeSet@1.2310, 2006-10-23 14:17:57+05:00, bar@mysql.com +3 -0
  Bug#22823 gt and lt operators appear to be reversed in ExtractValue() command
  Problem: "greater than" and "less than" XPath operators appeared to have been
implemented in reverse.
  Fix: swap arguments to eq_func() and eq_func_reverse() to provide correct operation
result.

Pushed into 5.1.13-rpl

Appeared in 5.1.14 common

Thank you for your bug report. This issue has been committed to our source repository of
that product and will be incorporated into the next release.

If necessary, you can access the source repository and build the latest available version,
including the bug fix. More information about accessing the source trees is available at

    http://dev.mysql.com/doc/en/installing-source.html

Documented bugfix in 5.1.14 changelog.