I've used the following filter to include an ACF field into my search results.

add_filter( 'pre_get_posts', 'so_9224493_adjust_search_query');
function so_9224493_adjust_search_query( $query ) {
    if ( !is_admin() && $query->is_search ) { //the !is_admin() boolean ensures that this does not affect your dashboard
        $meta_query_arguments = array(
            array(
                'key' => 'item_number', //this is where you would put your meta key
                'value' => $query->query_vars['s'],
                'compare' => 'LIKE',
            ),
        );
        $query->set('meta_query', $meta_query_arguments);
    };
}

Sadly, it doesn't work. However, if it did work, I want to restrict the search to that field only. I don't want the title or content etc. of posts and pages.

Along the process, I stumbled across a more promising filter, so I've tried adapting it to my needs.

function ni_search_by_title_only( $search, &$wp_query ){
    global $wpdb;
    if ( empty( $search ) )
        return $search;
    $q = $wp_query->query_vars;
    $n = ! empty( $q['exact'] ) ? '' : '%';
    $search =
    $searchand = '';
    foreach ( (array) $q['search_terms'] as $term ) {
        $term = esc_sql( like_escape( $term ) );
        $search .= "{$searchand}($wpdb->postmeta.meta_value LIKE '{$n}{$term}{$n}')";
        $searchand = ' AND ';
    }
    if ( ! empty( $search ) ) {
        $search = " AND ({$search}) ";
        if ( ! is_user_logged_in() )
            $search .= " AND ($wpdb->posts.post_password = '') ";
    }
    return $search;
}
add_filter( 'posts_search', 'ni_search_by_title_only', 500, 2 );

This doesn't work. Ideally, it would NOT search all meta_value fields, but only those of a specify meta_key.

PS: I'm not interested in a plugin to achieve what I'm after

I've used the following filter to include an ACF field into my search results.

add_filter( 'pre_get_posts', 'so_9224493_adjust_search_query');
function so_9224493_adjust_search_query( $query ) {
    if ( !is_admin() && $query->is_search ) { //the !is_admin() boolean ensures that this does not affect your dashboard
        $meta_query_arguments = array(
            array(
                'key' => 'item_number', //this is where you would put your meta key
                'value' => $query->query_vars['s'],
                'compare' => 'LIKE',
            ),
        );
        $query->set('meta_query', $meta_query_arguments);
    };
}

Sadly, it doesn't work. However, if it did work, I want to restrict the search to that field only. I don't want the title or content etc. of posts and pages.

Along the process, I stumbled across a more promising filter, so I've tried adapting it to my needs.

function ni_search_by_title_only( $search, &$wp_query ){
    global $wpdb;
    if ( empty( $search ) )
        return $search;
    $q = $wp_query->query_vars;
    $n = ! empty( $q['exact'] ) ? '' : '%';
    $search =
    $searchand = '';
    foreach ( (array) $q['search_terms'] as $term ) {
        $term = esc_sql( like_escape( $term ) );
        $search .= "{$searchand}($wpdb->postmeta.meta_value LIKE '{$n}{$term}{$n}')";
        $searchand = ' AND ';
    }
    if ( ! empty( $search ) ) {
        $search = " AND ({$search}) ";
        if ( ! is_user_logged_in() )
            $search .= " AND ($wpdb->posts.post_password = '') ";
    }
    return $search;
}
add_filter( 'posts_search', 'ni_search_by_title_only', 500, 2 );

This doesn't work. Ideally, it would NOT search all meta_value fields, but only those of a specify meta_key.

PS: I'm not interested in a plugin to achieve what I'm after

• query
• search
• meta-query

1 Answer 1

I ended up using a simple meta_query:

$args = [
    'post_status'  => 'publish',
    'post_type'    => $post_type,
    'orderby'      => 'title',
    'order'        => 'ASC',
    'meta_query' => array(
        'relation' => 'OR',
        array(
            'key'           => 'my_acf_field',
            'value'         => $search_term,
            'compare'       => 'LIKE'
        ),
    )
];

$query = new WP_Query($args);