Use Laravel 5.3 Query Builder to replicate Eloquent ORM data structure for Sub Query - laravel

Question

I am trying to replicate the result set that I get when using Eloquent ORM, except with Laravel Query Builder. Basically using this code I can get the packs to appear nested within the products so that when I loop them on the view I can further loop the packs within each products. Seems pretty basic right (see result set below).
$get_posts_for_product = Product::where('active', 1)
->with('packs')
->get()->toArray();
I have tried a few ways using Query Builder to get this to work but it joins the packs inline as I thought it would.
What is the best way to get this same Array structure using Query Builder, I am aware that the result set is a different type of array and that is fine but for my project it must be done using Query Builder at this point.
Thanks.

Answer 1

I would say, that is why you have Eloquent: you don't have to worry about how to have those relationships together.
However incase you really want to achieve the same result I will demo this using two tables users and messages:
1st method:
Retrieve the users and transform it by querying the database for relationships:
$result = DB::table('users')->get()->transform(function ($user){
$user->messages = DB::table('messages')->where('user_id', $user->id)->get();
return $user;
});
Downside: Having many users means a lot of db query on messages table.
Upside: less codes to write
2nd method:
Retrieve both tables using all the ids of user to query the messages:
$users = DB::table('users')->get();
$messages = DB::table('messages')->whereIn('user_id', $users->pluck('id')->toArray())->get();
$result = $users->transform(function ($user) use ($messages){
$user->messages = $messages->where('user_id', $user->id)->values();
return $user;
});
Downside: The need to still transform it.
Upside: Less database trips. i.e two queries only.
3rd method
Looks like the second except that you can group messages by 'user_id' then you do no extra filter when transforming users result:
$user = DB::table('users')->get();
$messages = DB::table('messages')->whereIn('user_id', $user->pluck('id')->toArray())
->get()
->groupBy('user_id');
$result = $user->transform(function ($user) use ($messages){
$user->messages = $messages[$user->id];
return $user;
});
Downside: Same with two.
Upside: no extra filter when transforming users.
Other method
Join on both users and messages when querying then transform the response, or simply use it as it is.
PS: Eloquent uses query builder.
The answer is open for update.