Use custom query if main search query returns zero results in wordpress

Question

I have a search page where if the main search returns 0 results then the following query will be used.

The code is

$num_res = $wp_query->post_count;
$get_search_term = get_search_query();

if($num_res == 0)
{

    $args = array(
        'post_type'     => 'resources',
        'meta_key'      => 'resource_txt',
        'meta_value'    => $get_search_term,
        'meta_compare'  => 'LIKE' );
    $custom_query =  new WP_Query( $args );
}

Now I am getting an error which says "Not unique table/alias: 'wp_postmeta'"

When I print the second query in browser it says,

SELECT SQL_CALC_FOUND_ROWS 

DISTINCT wp_posts.ID FROM wp_posts 

INNER JOIN wp_postmeta ON ( wp_posts.ID = wp_postmeta.post_id ) 

LEFT JOIN wp_postmeta ON (wp_posts.ID = wp_postmeta.post_id) 

WHERE 1=1 

AND ( ( wp_postmeta.meta_key = 'resource_txt' AND CAST(wp_postmeta.meta_value AS CHAR) LIKE '%insurance claim%' ) ) 

AND wp_posts.post_type = 'resources' 

AND (wp_posts.post_status = 'publish' OR wp_posts.post_status = 'private') 

GROUP BY wp_posts.ID ORDER BY wp_posts.post_date DESC LIMIT 0, 10

Is it like, I have to close the previous query and then run the custom query. Any help is highly appreciated.

Answer 1

Exactly right about resetting it! You should use wp_reset_query(). Try this:

$num_res = $wp_query->post_count;
$get_search_term = get_search_query();

// No more work required for the query, so...
wp_reset_query();

if($num_res == 0)
{
    $args = array(
        'post_type'     => 'resources',
        'meta_key'      => 'resource_txt',
        'meta_value'    => $get_search_term,
        'meta_compare'  => 'LIKE' );
    $custom_query =  new WP_Query( $args );

    // Do stuff here.

    wp_reset_query();
}

It is a good habit to reset the query once you've retrieved what you need from it.

Answer 2

Try using 'pre_get_posts' hook instead of writing another query. Please go through the docs for more information.

 <?php
function search_posts( $query ) {

    // Make sure this only runs on the main query on the front page
    if ($query->is_main_query() ) {

        // Exclude posts that have been explicitly set to hidden
        $query->set('meta_query', array(
            'relation' => 'AND',
            // Include posts where the meta key isn't set
            array(
                'key'     => 'resource_txt',
                'value'   => $get_search_term, // A value must exist due to https://core.trac.wordpress.org/ticket/23268
                'compare' => 'LIKE',
            ),
        ) );

    }

}
add_action( 'pre_get_posts', 'search_posts' );
?>

Hope this helps!