Enable comments on old posts of a content type

When I initially created a content type, I chose to hide the comments.
I already edited the content type and enabled comments but that takes effect for new posts, comments stay hidden for old posts.

Now I need to enable comments on some content types, however I have 100s of old posts already created and don’t want to edit each of them to open comment settings.

If I use the MyPhpAdmin to directly access the database, how do I open comments on all old posts of a content type at once?

I used UPDATE 'node' SET 'comment' = '2' WHERE 'comment' = '1' but it didn’t work.

Drupal version: 


Source: https://www.drupal.org/taxonomy/term/22/feed