LEFT JOIN only first row

Question

I read many threads about getting only the first row of a left join, but, for some reason, this does not work for me.

Here is my structure (simplified of course)

Feeds

id |  title | content
----------------------
1  | Feed 1 | ...

Artists

artist_id | artist_name
-----------------------
1         | Artist 1
2         | Artist 2

feeds_artists

rel_id | artist_id | feed_id
----------------------------
1      |     1     |    1 
2      |     2     |    1 
...

Now i want to get the articles and join only the first Artist and I thought of something like this:

SELECT *
    FROM feeds 
    LEFT JOIN feeds_artists ON wp_feeds.id = (
        SELECT feeds_artists.feed_id FROM feeds_artists
        WHERE feeds_artists.feed_id = feeds.id 
    LIMIT 1
    )
WHERE feeds.id = '13815'

just to get only the first row of the feeds_artists, but already this does not work.

I can not use TOP because of my database and I can't group the results by feeds_artists.artist_id as i need to sort them by date (I got results by grouping them this way, but the results where not the newest)

Tried something with OUTER APPLY as well - no success as well. To be honest i can not really imagine whats going on in those rows - probably the biggest reason why i cant get this to work.

SOLUTION:

SELECT *
FROM feeds f
LEFT JOIN artists a ON a.artist_id = (
    SELECT artist_id
    FROM feeds_artists fa 
    WHERE fa.feed_id = f.id
    LIMIT 1
)
WHERE f.id = '13815'

Answer 1

If you can assume that artist IDs increment over time, then the MIN(artist_id) will be the earliest.

So try something like this (untested...)

SELECT *
  FROM feeds f
  LEFT JOIN artists a ON a.artist_id = (
    SELECT
      MIN(fa.artist_id) a_id
    FROM feeds_artists fa 
    WHERE fa.feed_id = f.feed_id
  ) a