Question

I currently have two tables, one for pages (objects) and one for images (media).

I want to get a list of all the pages in the system, and join a single image record onto each page record. It’s very close to working now, but it is returning all of the records, when I just want to get one back.

I’ve tried a few sub queries + Distinct, but not quite got it working yet.

Can anyone point me in the right direction. I’ve tried group by, but it doesn’t work after doing the sort and therefore brings back the wrong image.

SELECT title, 
   url, 
   media_file, 
   media_order
FROM ndxz_objects 
   LEFT JOIN ndxz_media ON ndxz_objects.id = ndxz_media.media_ref_id
WHERE `status` = 1
   AND `section_id` = 2
GROUP BY title, url, media_file, media_order
ORDER BY ndxz_objects.ord, ndxz_media.media_order

Answer 1

I didn’t find that query worked, this is what I used in the end.

SELECT title, url, media_file
FROM ".PX."objects
LEFT JOIN
    (
SELECT m1.media_id, m1.media_ref_id, m1.media_file, m1.media_order
    FROM ".PX."media AS m1
    LEFT JOIN ".PX."media AS m2 ON m1.media_ref_id = m2.media_ref_id AND m1.media_order    > m2.media_order
    WHERE m2.media_ref_id IS NULL        
    )
maxmedia ON ndxz_objects.id = maxmedia.media_ref_id
WHERE `status` = 1
AND `section_id` = 2
ORDER BY `ord`

I found this from the within group aggrigates section here which seems like a good group of sql examples