You have this:
$sql1 = “update “.$wpdb->prefix.”admentor_bannerstats set clickcount=clickcount+1 where id=$id”;

It just updates the clickcount for the id, but not bannerid.

Should be:
$sql1 = “update “.$wpdb->prefix.”admentor_bannerstats set clickcount=clickcount+1 where datum=’”.date(’Ymd’).”‘ and bannerid=$id”;