Wordpress query_posts orderby rand not working in category archive template

Question

I cannot get my Wordpress theme to randomise the posts I'm displaying in the category archives [I'm using it as a CMS]. The homepage randomises normally, and I am [I think] correctly altering the WP_query. Below is the exact args array:

array(4) { ["orderby"]=> string(4) "rand" ["order"]=> string(3) "ASC" ["posts_per_page"]=> string(2) "-1" ["category_name"]=> string(8) "branding" }

For easier reading it is:

orderby => rand
order => ASC
posts_per_page => -1
category_name => branding (or whatever the query_string brings in)

I get all the posts from the category, but they are in post date order.

Any clues? or alternate methods for shuffling the result of my WP_query in the have_posts?

Thanks.

************EDIT************

Sorry I should have been more clear about the args array above. It is a var_dump of the query array, not my arguments I am adding to the query.

    $args = array(
        'orderby'        => 'rand',
        'order'      => 'ASC',
        'posts_per_page' => '-1',
    );
    global $wp_query;           
    remove_all_filters('posts_orderby');
    $theq = array_merge($args, $wp_query->query);
    query_posts($theq);

I added the remove_all_filters as per Sheikh Heera suggestion, but it hasn't made a difference.

Answer 1

You might be better off creating a new query then. This should only be used on an taxonomy template though like category.php or taxonomy-yourcustomtaxonomy.php.

global $wp_query;

$term = $wp_query->queried_object;

$args=array(
    'orderby' => 'rand',
    'posts_per_page' => -1,
    'post_type' => 'post',
    'tax_query' => array(
            array(
                'taxonomy'  => $term->taxonomy,
                'field'     => 'slug',
                'terms'     => $term->slug,
                )
            )
    );

$new_query = null;
$new_query = new WP_Query($args);

while ($new_query->have_posts()) : $new_query->the_post(); ?>
    <div id="post-<?php the_ID(); ?>" <?php post_class(); ?>>
        <h2 class="entry-title"><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></h2>
        <div class="entry-meta"><?php // Meta ?></div><!-- .entry-meta -->
        <div class="entry-content"><?php the_content(); ?></div>
    </div>
<?php
endwhile;
wp_reset_postdata();

Answer 2

It could be another plugin that creating the problem but you can do as follows

remove_all_filters('posts_orderby');
$args=array(
    orderby => 'rand'
    order => 'ASC'
    posts_per_page => -1
    category_name => 'branding'
);
query_posts($args);

But remember, you can wreck a plugin's functionality with this solution, but it could be useful to solve the problem but may be not perfect.