What are WordPress orphan posts meta and how to clean them?
Post metadata includes information about each post, such as the author, the date it was written or posted, and its categories. Sometimes, post metadata becomes orphaned, meaning it no longer belongs to any existing post. These “orphan post meta” entries are unnecessary and should be cleaned.
You can either use our Advanced Database Cleaner plugin to remove these orphan post meta or run the following SQL code (used by the plugin) directly via phpMyAdmin:
DELETE pm FROM postmeta pm LEFT JOIN posts wp ON wp.ID = pm.post_id WHERE wp.ID IS NULL