What are WordPress orphan comments meta and how to clean them?
Comment metadata includes details about each comment, such as the author and the date it was posted. Occasionally, some comment metadata becomes orphaned, meaning it no longer corresponds to any existing comment. These “orphan comment meta” entries are unnecessary and should be cleaned.
To remove orphan comment meta, you can either use our Advanced Database Cleaner plugin or run the following SQL code (used by the plugin) directly via phpMyAdmin:
DELETE FROM commentmeta WHERE comment_id NOT IN (SELECT comment_id FROM comments)