Sidebar if Query

Hey

I have this query which I’m using in the sidebar, but when I place it in a php widget, the whole sidebar disappears… The code is below and the full sidebar code is in a pastebin here https://pastebin.com/FdPrsEJN.

Any ideas?

global $wp_query;
$postid = $wp_query->post->ID;
if ( ! empty( get_post_meta($postid, 'TourURL', true) ) ) echo '<P>Show Link</P>';
else echo '<P>No Link</P>';
wp_reset_query();

Thanks