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?