Mysql Query Group Concat Limit multiple record of child table in single query

Question

Album Table:

+------------------------------+
| id      name       updated_at|
+------------------------------+

Album_member Table:

+------------------------------------+
| id      album_id         member_id |
+------------------------------------+

Album_media Table:

+--------------------------------+
| id       album_id         link |
+--------------------------------+

My Query:

$limit = 30;
$member_id = 1;
SELECT a . *,
(SELECT GROUP_CONCAT(CONCAT('$assets/album_image/medium/', ds_album_media.link) SEPARATOR ',') as link
FROM ds_album_media WHERE ds_album_media.album_id = a.id ORDER BY a.updated_at desc LIMIT 0 , 5)
AS photo_link FROM `ds_album` a
LEFT JOIN ds_album_media amd ON amd.album_id = a.id
LEFT JOIN ds_album_member amb ON amb.album_id = a.id
where amb.member_id = " . $member_id . " GROUP BY a.id
ORDER BY a.updated_at desc LIMIT 0 , $limit

Now for each album there is multiple album_media and album_member is for which album user is following i want data in such a way that retrieve all album that use follows and all photos of that album but constrains is that need to set album_media limit 5 and album limit 30.

1. limit not working as i have used group_concat any other way to limit the records of group_concat?

2. I am using laravel so any solution regarding that is also most welcome.

I have used substring_index() function but is it sufficient way in perspective of performance?

I have tried this query with laravel,

Laravel Query(Edit):

$data = Album::select("album.*")
    ->leftjoin("album_media", 'album_media.album_id', '=', 'album.id')
                    ->leftjoin("album_member", 'album_member.album_id', '=', 'album.id')
    ->where('album_member.member_id', $member_id)
    ->with(['albumMedia' => function($query) {
       return $query->where('album_id','album.id')->take(5);
    }])
    ->groupBy('album.id')->orderBy('album.updated_at', 'desc')->take($limit)->skip($skip)->get()->toArray();

Answer 1

Set up your relationships and then constrain them like so:

$albums = Album::with('albumMedia', 'albumMembers')
->whereHas('albumMembers', function($query) use ($userId) {
    $query->where('albumMembers.member_id', $userId);
})
->orderBy('album.updated_at')
->take($limit)
->skip($skip)
->get();

Lastly, you could then add a method to the Album model which will help you retrieve your concatenated string/link, based on the eagerly-loaded relationship.

Better yet, instead of doing a whereHas, you could so something like a scope method on the Album model which will create it for you. This would be much cleaner than the example above.