/******************************************
 
The Base Model
 
******************************************/
<?php
 
namespace App;
 
use Illuminate\Support\Facades\DB;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Query\Builder;
 
class BaseModel extends Model {
 
    /**
     * query scope nPerGroup
     *
     * @return void
     */
    public function scopeNPerGroup($query, $group, $n = 10)
    {
        // queried table
        $table = ($this->getTable());
 
        // initialize MySQL variables inline
        $query->from( DB::raw("(SELECT @rank:=0, @group:=0) as vars, {$table}") );
 
        // if no columns already selected, let's select *
        if ( ! $query->getQuery()->columns)
        {
            $query->select("{$table}.*");
        }
 
        // make sure column aliases are unique
        $groupAlias = 'group_'.md5(time());
        $rankAlias  = 'rank_'.md5(time());
 
        // apply mysql variables
        $query->addSelect(DB::raw(
            "@rank := IF(@group = {$group}, @rank+1, 1) as {$rankAlias}, @group := {$group} as {$groupAlias}"
        ));
 
        // make sure first order clause is the group order
        $query->getQuery()->orders = (array) $query->getQuery()->orders;
        array_unshift($query->getQuery()->orders, ['column' => $group, 'direction' => 'asc']);
 
        // prepare subquery
        $subQuery = $query->toSql();
 
        // prepare new main base Query\Builder
        $newBase = $this->newQuery()
            ->from(DB::raw("({$subQuery}) as {$table}"))
            ->mergeBindings($query->getQuery())
            ->where($rankAlias, '<=', $n)
            ->getQuery();
 
        // replace underlying builder to get rid of previous clauses
        $query->setQuery($newBase);
    }
 
}
 
 
 
/***********************************************************
 
The Board Model extending it
 
***********************************************************/
<?php
 
namespace App;
 
use App\BaseModel;
 
class Board extends BaseModel
{
 
    public function pins()
    {
        return $this->hasMany('App\Pin');
    }
 
    public function recentPins()
    {
        return $this->pins()->latest()->nPerGroup('board_id', 5);
    }
}
 
 
 
/***********************************************************
 
Calling the method in Tinker
 
***********************************************************/
 
App\Board::with('latestComments')->get();