Laravel 4, messy Eloquent join query - php

Question

I'm working on somehow messy project where structure of db is:
Object
id, title, description, url ... [and some more columns]
ObjectMeta
object_id, variable, value
So let's give you:
Object: 1, 'Cool Book', 'This cool book is just for you!', ...
Object Meta:
1, 'author_name', 'John Doe'
1, 'released', 2014
1, 'price', 23.22
1, 'url', 'http://amazon.com/coolbook'
1, 'genre', 3
So I need to perform query which will:
Pull all Objects that has genre 3, then sort those Objects by their released date.
$objs = static::Active()
->where('object', '=', $object)
->where('category','=',$category)
->whereIn('site_id', array(self::$site_id, 0))
->leftJoin('object_meta', function($join)
{
$join->on('object.id','=', 'object_meta.content_id');
})
->where('object_meta.variable', 'genre')
->where('object_meta.value', 3);
->where('object_meta.variable', 'released');
->orderBy('object_meta.value', 'desc');
->groupBy('object.id')
->paginate(20);
This query has 0 results even if there are plenty of those books out there. I know that the second object_meta.variable where is guilty here. How can I write this query to make it work?
Really appreciating your help.
-- Edit
I've created workaround but it's really, really bad workaround (funny thing is that I swear the query above was working for month or so).
$objs = static::Active()
->where('object', '=', $object)
->where('category','=',$category)
->whereIn('site_id', array(self::$site_id, 0))
->leftJoin('object_meta', function($join)
{
$join->on('object.id','=', 'object_meta.content_id');
})
->where('object_meta.variable', 'genre')
->where('object_meta.value', 3);
->groupBy('object.id')
->get();
foreach($objs as $obj)
{
$obj->id = $obj->object_id;
$objs_meta = ObjectMeta::where('object_id',$obj->object_id)->get();
foreach($objs_meta as $obj_meta)
{
$variable = $obj_meta->var;
$obj->$variable = $obj_meta->value;
}
}
$objs = $objs->sortBy(function($role){
return $role->released;
});
$objs = Paginator::make($objs->toArray(), sizeof($objs), $limit);

Answer 1

You need inner join (join()) not leftJoin(), and you need it twice:
$objs = static::Active()
->where('object', '=', $object)
->where('category','=',$category)
->whereIn('site_id', array(self::$site_id, 0))
->join('object_meta as genre', function ($join) {
$join->on('object.id', '=', 'genre.content_id')
->where('genre.variable', '=', 'genre')
->where('genre.value', '=', 3);
})
->join('object_meta as released', function ($join) {
$join->on('object.id', '=', 'released.content_id')
->where('released.variable', '=', 'released');
})
->orderBy('released.value', 'desc');
->select('object.*', 'released.value as released')
->distinct()
// or group by, doesn't matter in your case
// ->groupBy('object.id')
->paginate(20);
Then your objects will have additional property released with appropriate value.
According to the comments:
If you want to dynamically add the joins, then I suggest scopes like below:
public function scopeGenre($query, $value)
{
$query->join('object_meta as genre', function ($join) use ($value) {
$join->on('object.id', '=', 'genre.content_id')
->where('genre.variable', '=', 'genre')
->where('genre.value', '=', $value);
});
}
then:
$query->where(..)->genre(3)->...