If you need to maintain a proper audit trail for every state change, you need a separate table for that. Any trick you play with a fixed number of scalar colum

If you need to maintain a proper audit trail for every state change, you need a separate table for that. Any trick you play with a fixed number of scalar columns will only let you access the timestamp of the last change of the same type. This won't be particularly useful when there's an edit war among moderators who unpublish and republish the same thing over and over.