SQL Combine SELECT and UPDATE (inclusive of REPLACE and SUBSTRING_INDEX)

Evening guys and girls!

I’m trying to combine both a SELECT and UPDATE, however the join is causing me a major headache and hoping someone can help.

My table is within wordpress post data containing other text, images etc and contain the following: About 9000 unique posts / videos(All with unique video file names)

I’m trying to make the string:

I’ve figured out how to obtain the filename using:

SELECT SUBSTRING_INDEX(SUBSTRING_INDEX(post_content,'"][/video]',1),'')
WHERE post_content LIKE '%[video preload="none"%';