Nothing but the table, unread comments are not periodic
so how do you suggest I (keep in a plate unread comments), you can make VC, so you can open up a dialogue, and if you were not on the screen, they will not be read. Too funny thing.
Suppose that the system was 100500 users, after adding a new comment you will need to add all the information about the new unread comments? And if the comment is edited? What about new users?
Properly store the view and not "unread comments":
id, user_id, text, ...
id, comment_id, user_id, ...