I have multiples custom field in a post type. i can save data, update and display, all fine. now I'm doing the search engine. as it is a library, it must be possible to search in specific fields (custom field), publisher, country, etc. Here the code I have for publisher...

i open a variable

    function register_query_vars( $vars ) {
    $vars[] = 'publisher'; //
    return $vars;
add_filter( 'query_vars', 'register_query_vars' );

search form by publisher in shortcode

function publisher_search() {
    add_shortcode( 'search_form_publisher', 'search_form_publisher' );
add_action( 'init', 'publisher_search' );


function search_form_publisher( $atts ){
    $output = '<form action="' . esc_url( home_url() ) . '" method="get" role="search">';
    $output .= '<input type="text" name="publisher" value="' . get_search_query() . '" class="field" placeholder="Search..."/>';
    $output .= '<input type="hidden" name="post_type" value="books" />';
    $output .= '<input type="submit" value="Search!" class="button" />';
    $output .= '</form>';
    return $output;

so far, all good. when searching, the following url is built:


which uses the archive-{post-type}.php template

$args = array(
  'post_type'      => 'books',
  'post_status'    => 'publish',
  'meta_query'     => array(
      'key'     => 'publisher',
      'value'   => get_query_var('publisher'),
      'compare' => 'LIKE',


// The Query
$the_query = new WP_Query( $args );

// The Loop
if ( $the_query->have_posts() ) {

    while ( $the_query->have_posts() ) : $the_query->the_post(); 
        // Your code here


} else {
        echo 'no posts found';
/* Restore original Post Data */

I print the value of the custom field publisher like this, its work well:

function publisher() {
    global $wp_query;
    $post = $wp_query->post;
    $publisher = get_post_meta($post->ID, 'publisher', true);
    if (!empty($publisher)) {
        echo $publisher;

The problem is, however, that the query does not return any results. the print is this:

Array ( [post_type] => books [post_status] => publish [meta_query] => Array ( [0] => Array ( [key] => publisher [value] => Harvard [compare] => LIKE ) ) )

that is, if it collects the value of the search term. I have tried many codes that I have found on the internet but none of them work. I think that a function that adds a posts_search filter, but the ones I have tried do not work.

I would appreciate your help to resolve the issue.I'm lost. Thank you!!

  • Your code seems fine (although in the publisher() function, you should just use get_post() to get the current post or get_the_ID() to get just the post ID), so are you 100% sure there are books posts with the meta publisher containing Harvard/harvard in the value? Try echo $the_query->request; and see if the SQL is good. And try adding 'suppress_filters' => true to your $args just to see if a code is modifying your args - does suppressing filters return any results?
    – Sally CJ
    Jan 9, 2021 at 9:42
  • 1
    And I think it'd be much better if you use a custom taxonomy (named publisher) than using the post meta. Because taxonomies are better suited at grouping things together and taxonomy queries also run faster than meta queries.
    – Sally CJ
    Jan 9, 2021 at 9:52
  • 1
    okay. thank you for the recommendations. It helped me a lot to do echo $ the_query-> request because although the SQL query it does is fine, the point is that it is not looking at the correct table because I have a specific table for the custom fields.
    – Oox
    Jan 9, 2021 at 18:14
  • The query is: SELECT SQL_CALC_FOUND_ROWS wp_8_posts.ID FROM wp_8_posts INNER JOIN wp_8_postmeta ON ( wp_8_posts.ID = wp_8_postmeta.post_id ) WHERE 1=1 AND ( ( wp_8_postmeta.meta_key = 'publisher' AND wp_8_postmeta.meta_value LIKE '{}Harvard{}' ) ) AND wp_8_posts.post_type = 'books' AND ((wp_8_posts.post_status = 'publish')) GROUP BY wp_8_posts.ID ORDER BY wp_8_posts.post_date DESC LIMIT 0, 10. My table with custom field is `wp_8_postmeta_books' See: link
    – Oox
    Jan 9, 2021 at 18:19
  • so probably if i need a post_search filter??
    – Oox
    Jan 9, 2021 at 18:22

1 Answer 1


After thinking about the problem, I found the simplest solution, do a direct query using $wpdb

in archive-{post-type}.php


global $wpdb;
$meta_key = get_query_var('publisher');
$result = $wpdb->get_results("
    SELECT  * 
    FROM  " . $wpdb->prefix. "postmeta_books 
    WHERE publisher LIKE  '%$meta_key%' 
foreach( $result as $results ) {

        echo $results->publisher;
        echo '<br/>';


It is the basic query, it needs to be refined but I wanted to share it to close the question. of course work very well.


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