gerald@wpcustoms on "SQL: change post custom field to CPT post taxonomy"

Hello,

the setup is as follow:
I have regular posts with a custom field: actor = 'tom hanks'
for advanced management I now created a custom post type (actors) and added "tom hanks" as a post within that actors taxonomy.
Via plugin 'Advanced custom fields' I connected the custom taxonomy (actors) to the regular posts so I can select 'tom hanks' on the regular post page.

This can be done manually (check the custom field value and click the according actors category) but there are way more than 1500 posts and many other similar custom field values.

Do you have any idea how that can be solved via SQL query or function?

in one line:
get customfield 'actors' and move to taxonomy('actors') for that post.

If somebody can please help me out with the query for a mysql or similar you would definitely make my day :)

Thanks for taking the time.
gerald