Migrating meta value to new meta value

Question

There is a "_thumbnail_id" meta key for our logos and it has each value (Id) by post id.

However, we created a new logo field ( meta key = _logo) for logo image ids. We need to move meta value from "_thumbnail_id" to "_logo" in all posts.

I have searched and tested some. But there is a problem. Most of the posts have "_thumbnail_id". but posts don't have the new meta key (_logo) by the post ids. Because it's new one.

Do I need to add new meta value first in all post? ( _logo ) And then migrate the old one (_thumbnail_id) to the new one (_logo)?

How can I move the meta value to new one?

Thanks,

Answer 1

Back up your database first, then run this query in phpMyAdmin (or if you don't have phpMyAdmin, run the query out of functions.php on an admin hook using $wpdb->query):

UPDATE wp_postmeta SET meta_key = '_logo' WHERE meta_key = '_thumbnail_id'

This will preserve all of the current IDs and just change the name of the meta key. No need to duplicate information or change them one by one.