如何从联结表中检索值作为字符串？

Question

I have 3 tables in MYSQL, VideoCategory is the junction table between Video and category

Video
Category
VideoCategory

it means: each video can bleong to many categories (VideoCategory) table.

My goal is to retrieve a "SMART" way of these values: it means: Video, Comma Delimied String of Categories

ex:

"video1", "1, 2, 3"
"video2", "1, 4"
"video"3", ""

(video 3 has no categories assigned)

Any idea on how to do that without using mysql loops ?

Answer 1

group_concat and a couple of join s should do the trick:

SELECT video.name, 
       GROUP_CONCAT(category.name ORDER BY category.name SEPARATOR ', ')
FROM   video v
JOIN   videocategory vc ON v.id = videocategory.video_id
JOIN   category c ON videocategory.category_id = c.id