What is the correct/safe way to delete all comments?

Question

We've inherited a WordPress (3.3.2) site that has 13k pending comments, all of which are spam.

To delete all these comments is it sufficient and safe enough to do:

DELETE FROM wp_comments;  
DELETE FROM wp_commentmeta;

...or alternatively TRUNCATE both tables in the database?

Answer 1

Yes. That will be sufficient. And I highly recommend that you activate the Akismet plugin to block spam. Probably if you think there might be any genuine comments in the 13k pending ones, then install and activate Akismet first. Then go to Comments in the Wordpress Dashboard, and click on 'Check for Spam'. It should automatically move all spam to the Spam folder.