Include one custom field in search results

Question

I have custom search template on which I would like that search results include value of one custom field. I tested this code to include custom fields in WP search results, and it works just fine. But, it search through all custom fields. In case there are many diferent custom fields it will slow down search, and of course there is no need that all custom fields are searchable, sometimes it just populate search results with irrelevant results.

I would like to allow searching of just one custom field, on custom search template. Ideally on that template I do not even need to search for post title/content, just for content of that custom field.

How to include just particular custom field in search results?

UPDATE

$search_term = get_search_query(); // Get current search term
$args = array(
     'post_type' => 'post', // Post type is post.
     'post_status' => 'publish', // Post is published.
     'posts_per_page' => 4, // Posts per page.
     'meta_query' => array(
                         array(
                                 'key'     => 'my_custom_field', // Custom field to search
                                 'value'   => $search_term, // Value of custom field is search term
                                 'compare' => 'LIKE',
                            ),
                        ),
            );
$my_query = new WP_Query($args);
if( $my_query->have_posts() ) {
while ($my_query->have_posts()) : $my_query->the_post();
include 'post-content.php';
endwhile;
}
wp_reset_query();

I managed to get results from one custom field, with code above, but I lost pagination. Now I have no content on /page/x. How to allow pagination in this case?

Answer 1

I would ignore the article entirely and use a meta query:

$query = new WP_Query([
    'meta_query' => [
        [
            'key'     => 'my_custom_field',
            'value'   => 'search_term',
            'compare' => 'LIKE',
        ]
    ]
]);