Taxonomy queries without joins ignore order by

[Chad Killingsworth]

Using a category exclusion term on a query causes the posts to be ordered ascending. Example

​http://site/feed/?cat=-1

I was able to work around the problem by not including a GROUP BY clause when $join variable is empty. I've attached the patch but I'm not sure this is the best solution.

[Chad Killingsworth]

Query.php patch for group by/order by conflict

[scribu]

(yes, I'm actually reviewing this time)

[hakre]

Thanks for reporting and scribu thanks a lot for your support, please fix if you can for 3.1.1.

[scribu]

Related: #16814

[scribu]

$groupby doesn't affect $orderby in any way, so this is really strange.

Please add the following lines of code somewhere after The Loop and paste here what you get when you go to ?cat=-1

echo '<pre>';
print_r($wp_query->query_vars);
print_r($wp_query->request);

[scribu]

Also, make sure this is not caused by a plugin.

[Chad Killingsworth]

I have a test instance setup and I disabled all plugins before I began testing/debugging the issue. I agree with your statement about the strangeness of the group by/order by conflict. The SQL Statement including the group by clause looks perfectly valid to me and I don't understand why it would affect post ordering in any way.

Here's the query variables and request output:

Array
(
    [cat] => -1
    [feed] => atom
    [error] => 
    [m] => 0
    [p] => 0
    [post_parent] => 
    [subpost] => 
    [subpost_id] => 
    [attachment] => 
    [attachment_id] => 0
    [name] => 
    [static] => 
    [pagename] => 
    [page_id] => 0
    [second] => 
    [minute] => 
    [hour] => 
    [day] => 0
    [monthnum] => 0
    [year] => 0
    [w] => 0
    [category_name] => 
    [tag] => 
    [tag_id] => 
    [author_name] => 
    [tb] => 
    [paged] => 0
    [comments_popup] => 
    [meta_key] => 
    [meta_value] => 
    [preview] => 
    [s] => 
    [sentence] => 
    [fields] => 
    [category__in] => Array
        (
        )

    [category__not_in] => Array
        (
            [0] => 1
        )

    [category__and] => Array
        (
        )

    [post__in] => Array
        (
        )

    [post__not_in] => Array
        (
        )

    [tag__in] => Array
        (
        )

    [tag__not_in] => Array
        (
        )

    [tag__and] => Array
        (
        )

    [tag_slug__in] => Array
        (
        )

    [tag_slug__and] => Array
        (
        )

    [meta_query] => Array
        (
        )

    [ignore_sticky_posts] => 
    [suppress_filters] => 
    [cache_results] => 1
    [update_post_term_cache] => 1
    [update_post_meta_cache] => 1
    [post_type] => 
    [posts_per_page] => 10
    [nopaging] => 
    [comments_per_page] => 50
    [no_found_rows] => 
    [order] => DESC
    [orderby] => wp_1_posts.post_date DESC
)
 SELECT SQL_CALC_FOUND_ROWS  wp_1_posts.* FROM wp_1_posts  WHERE 1=1  AND ( wp_1_posts.ID NOT IN (
					SELECT object_id
					FROM wp_1_term_relationships
					WHERE term_taxonomy_id IN (1)
				) ) AND wp_1_posts.post_type = 'post' AND (wp_1_posts.post_status = 'publish' OR wp_1_posts.post_status = 'private') GROUP BY wp_1_posts.ID ORDER BY wp_1_posts.post_date DESC LIMIT 0, 10

[scribu]

It works ok for me.

Try running that query directly through phpMyAdmin and see if it still happens.

[Chad Killingsworth]

On my SQL Server, the results returned in reverse order (i.e. the problem still occurs). I'm running 5.0.51b-community-nt on a 64bit windows server.

[Chad Killingsworth]

It looks like it may be this MySql bug: ​http://bugs.mysql.com/bug.php?id=32202

I can simply upgrade our MySql server, but since this is a supported version for Word Press, you may want to still work around the issue.

[scribu]

Please try the patch on #16826 and let me know if the bug still occurs.

[Chad Killingsworth]

That patch does indeed fix the issue.

[scribu]

Cool; two bird with one stone. :)

[scribu]

Seems we can't rely on #16826.

[ryan]

Unless we have a simple workaround, this might be wontfix since it is apparently due to a bug in a particular version of MySQL.

[scribu]

I've tried some variations on the current patch, but it didn't help.

I think those affected will just have to wait for the next minor release of MySQL or upgrade to MySQL 5.1.