How to get single row having one column different data.

I have three table Instructors, Inst_avatar, Inst_certificate. where Inst_certificate can have multiple Instructors.

this is my code

protected function getInsrtuctorInfo($vendor_id){
        $instructors = DB::table('instructors')               
                        ->leftJoin('map_instructors_profile_snap', 'instructors.id', '=', 'map_instructors_profile_snap.instructor_id')                              
                        ->leftJoin('map_instructors_certificates', 'instructors.id', '=', 'map_instructors_certificates.instructor_id')
                        ->where('instructors.vendor_id', $vendor_id)            
                        ->select(DB::raw('
                                instructors.id as instructor_id, instructors.name as instructor_name, instructors.bio as instructor_bio, map_instructors_profile_snap.link as avatar, map_instructors_certificates.link as certificate'))
                        ->get();        
            return $instructors; 
    } 

after dd($instructors) i am getting

Collection {#346 ▼
  #items: array:2 [▼
    0 => {#344 ▼
      +"instructor_id": 4
      +"instructor_name": "ABC"
      +"instructor_bio": """
        <p>Lorem Ipsum</p>\r\n
        <p> </p>
        """
      +"avatar": "1476356667.jpg"
      +"certificate": "1476356649.jpg"
    }
    1 => {#350 ▼
      +"instructor_id": 4
      +"instructor_name": "ABC"
      +"instructor_bio": """
        <p>Lorem Ipsum</p>\r\n
        <p> </p>
        """
      +"avatar": "1476356667.jpg"
      +"certificate": "1485842659.jpg"
    }
  ]
}

how can i fox this?