Searchable meta value in user.php

Question

I have created a new column in the user table list (admin page) and would like the column to be searchable in the search query, How do i add the meta to the search users query ?

/**
 * Create user column (admin panel)
 */
add_filter( 'manage_users_columns', 'new_modify_user_table' );
function new_modify_user_table( $column ) 
{
    $column['kundnummer'] = 'Kundnummer';
    return $column;
}

/**
 * Add content to user column (admin panel)
 */
add_filter( 'manage_users_custom_column', 'new_modify_user_table_row', 10, 3 );
function new_modify_user_table_row( $val, $column_name, $user_id ) 
{
    switch ($column_name) {
        case 'kundnummer' :
            return get_user_meta( $user_id, 'woocommerce_customer_id', true );
            break;
        default:
    }
    return $val;
}

Solution

/**
 * Searching Meta Data in Admin
 */
add_action('pre_user_query','yoursite_pre_user_search');
function yoursite_pre_user_search($user_search) {
    global $wpdb;
    if (!isset($_GET['s'])) return;

    //Enter Your Meta Fields To Query
    $search_array = array("customer_id", "woocommerce_customer_id", "first_name", "last_name");

    $user_search->query_from .= " INNER JOIN {$wpdb->usermeta} ON {$wpdb->users}.ID={$wpdb->usermeta}.user_id AND (";
    for($i=0;$i<count($search_array);$i++) {
        if ($i > 0) $user_search->query_from .= " OR ";
            $user_search->query_from .= "{$wpdb->usermeta}.meta_key='" . $search_array[$i] . "'";
        }
    $user_search->query_from .= ")";        
    $custom_where = $wpdb->prepare("{$wpdb->usermeta}.meta_value LIKE '%s'", "%" . $_GET['s'] . "%");
    $user_search->query_where = str_replace('WHERE 1=1 AND (', "WHERE 1=1 AND ({$custom_where} OR ",$user_search->query_where);

}