How to make such a query in the database?

Question

MySQL

The essence of the request is as follows: There is a video on the main page, at the bottom of it I make the "Related Videos" block. So, you need to select all videos from the videos table (in this block), but they must be of the same category as the main video. What to do?
The db structure is here:

Answer 1

SELECT * FROM videos
WHERE id IN (
     SELECT video_id FROM video_category
     WHERE category_id=3
)