Question

This is probably very basic, but I’m not experienced at all with sub selects.

I have two tables: prm_album and gallery_meta. prm_album stores name and id for each album, gallery_meta stores image details for every image of every album. The involved columns are thus:

prm_album:        ID, Name
gallery_meta:     FileName, AlbumID, FileExt, IsDefault, Created

I’m trying to combine two queries – one gave me a list of albums, another gave me thumbnail info for each of those albums. I want to end up with a single array this time where I can get each album’s name, id, and it’s default (or first) image’s info.

SELECT a.ID, a.Abbr, a.Name, p.FileName, p.FileExt 
FROM prm_album a
LEFT JOIN ( 
    SELECT FileName, FileExt
    FROM gallery_meta 
    ORDER BY (IsDefault = 1) DESC, Created ASC
    LIMIT 0,1 ) AS p
ON (a.ID = p.AlbumID)
WHERE 1

When put through the console, this throws the error Unknown column 'p.AlbumID' in 'on clause'. All advice appreciated.

Answer 1

SELECT a.ID, a.Abbr, a.Name, p.FileName, p.FileExt 
FROM prm_album a
LEFT JOIN gallery_meta p
  ON p.AlbumID=a.ID
GROUP BY a.ID
ORDER BY p.IsDefault DESC, p.Created ASC