Include Taxonomies in Search Results

January 12, 2022

This will search Posts and Post Types for Taxonomies that match the search terms and will return the Posts (not the taxonomies).

function taxonomy_search_where($where){
  global $wpdb;
  if (is_search())
    $where .= "OR (t.name LIKE '%".get_search_query()."%' AND {$wpdb->posts}.post_status = 'publish')";
  return $where;
}

function taxonomy_search_join($join){
  global $wpdb;
  if (is_search())
    $join .= "LEFT JOIN {$wpdb->term_relationships} tr ON {$wpdb->posts}.ID = tr.object_id INNER JOIN {$wpdb->term_taxonomy} tt ON tt.term_taxonomy_id=tr.term_taxonomy_id INNER JOIN {$wpdb->terms} t ON t.term_id = tt.term_id";
  return $join;
}

function taxonomy_search_groupby($groupby){
  global $wpdb;

  // we need to group on post ID
  $groupby_id = "{$wpdb->posts}.ID";
  if(!is_search() || strpos($groupby, $groupby_id) !== false) return $groupby;

  // groupby was empty, use ours
  if(!strlen(trim($groupby))) return $groupby_id;

  // wasn't empty, append ours
  return $groupby.", ".$groupby_id;
}

add_filter('posts_where','taxonomy_search_where');
add_filter('posts_join', 'taxonomy_search_join');
add_filter('posts_groupby', 'taxonomy_search_groupby');

Source.