UPDATE vn.ticket t
        JOIN vn.ticketObservation o ON o.ticketFk = t.id
    SET t.weight = cast(REPLACE(o.description, ',', '.') as decimal(10,2))
        WHERE o.observationTypeFk = 6;

DELETE FROM vn.ticketObservation WHERE observationTypeFk = 6;
DELETE FROM vn.observationType WHERE id = 6;
