I'm trying to replace the $wp_query object for a specific category, without having to deal with creating a new template and creating a new WP_Query object there.

My aim is to change the data available to The Loop from the default for that request to a custom query.

add_filter( 'pre_get_posts', 'custom_wpquery' );

function custom_wpquery( $query ){
global $wp_query;
   if (is_category(121)) {
             if ($wp_query === $query) {
                   $query = new WP_Query('page_id=146');
                   $query->set('page_id', 146);
  return $query;

That doesn't seem to affect The Loop at all, what am I doing wrong?

1 Answer 1


This seems to work, but I would be interested in hearing from others if it's the "correct" way to provide this sort of override. I'm assuming you're visiting a category archive page, like http://www.example.com/category/computers/.

// landing page = 188
// category = "computers" (#8)

function custom_wpquery( $query ){
    // the main query
    global $wp_the_query;

    if ( 'computers' === $query->get( 'category_name' ) ) {
        if ( $wp_the_query === $query) {
            // reset and override the active query
            $query->query( 'page_id=188' );
add_filter( 'pre_get_posts', 'custom_wpquery' );

This should probably test $query->is_archive, as well.

  • A couple thoughts not specific to the question: you need to return $query because it's a filter, and in 3.3 you'll be able to use is_main_query() instead of global-ing and comparing to $wp_the_query. Also, you might as well combine the two if's :) Oct 16, 2011 at 15:20
  • pre_get_posts is an action (do_action_ref_array()), and $query is passed by reference, so $query doesn't need to be returned. Good point, regarding the combined if. Oct 16, 2011 at 16:02
  • 1
    Ah, you're right. I've only ever used it as a filter, and have been conditioned to go "OH NO" if I see a filter without a return :) Oct 19, 2011 at 14:37

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