Mixing regular and custom post types (with meta_query) on home page

The question:

Not sure how to achieve this. I’m trying to mix standard posts and custom posts on a site homepage but I only want to display the custom posts if a meta value is set. Displaying the posts works fine 'post_type' => array('game', 'post') but when I add in the meta_query the regular posts are no longer displaying (which makes sense as they don’t meet the meta_query condition).

So how do I limit the meta_query to only the custom post type so that the regular post will still be included?

The Solutions:

Below are the methods you can try. The first solution is probably the best. Try others if the first one doesn’t work. Senior developers aren’t just copying/pasting – they read the methods carefully & apply them wisely to each case.

Method 1

There are different way to do the trick, 2 comes into my mind:

  1. use a complete custom $wpdb query
  2. use WP_Query with filters, using WP_Meta_Query to build the additional sql

I’ll post here sample code for case #2

/**
 * Run on pre_get_posts and if on home page (look at url)
 * add posts_where, posts_join and pre_get_posts hooks
 */
function home_page_game_sql( $query ) {
  // exit if is not main query and home index
  if ( ! ( $query->is_main_query() && ! is_admin() && is_home() ) ) return;
  add_filter( 'posts_where', 'home_page_game_filter' );
  add_filter( 'posts_join', 'home_page_game_filter' );
}
add_action('pre_get_posts', 'home_page_game_sql');


/**
 * Set the SQL filtering posts_join and posts_where
 * use WP_Meta_Query to generate the additional where clause
 */
function home_page_game_filter( $sql = '' ) {
  // remove filters
  remove_filter( current_filter(), __FUNCTION__);
  static $sql_game_filters;
  if ( is_null($sql_game_filters) ) {
    // SET YOUR META QUERY ARGS HERE
    $args = array(
      array(
        'key' => 'my_custom_key',
        'value'   => 'value_your_are_looking_for',
        'compare' => '='
      )
    );
    $meta_query = new WP_Meta_Query( $args );
    $sql_game_filters = $meta_query->get_sql('post', $GLOBALS['wpdb']->posts, 'ID');
  }
  // SET YOUR CPT NAME HERE
  $cpt = 'game';
  global $wpdb;
  if ( current_filter() === 'posts_where' && isset($sql_game_filters['where']) ) {
    $where = "AND ($wpdb->posts.post_status = 'publish') ";
    $where .= "AND ( $wpdb->posts.post_type = 'post' OR ( ";
    $where .= $wpdb->prepare( "$wpdb->posts.post_type = %s", $cpt);
    $where .= $sql_game_filters['where'] . ' ) )';
    $where .= " GROUP BY $wpdb->posts.ID ";
    return $where;
  }
  if ( current_filter() === 'posts_join' && isset($sql_game_filters['join']) ) {
    return $sql .= $sql_game_filters['join'];
  }
}

See inline comments for further explaination.

Also look at WP_Meta_Query on Codex for complete docs on how to set your meta query args.


Edit

I refactored code in a reusable plugin, using a class. Available as Gist.


All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0

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