has_shortcode() – how to detect nested shortcode

$page_id = get_queried_object_id();
$page_object = get_page( $page_id );
if ( strpos($page_object->post_content, '[/slider]') )

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)