Laravel 5.4 join concat pluck

Question

I am writing an assignment system for biodata record. The data tables:

preceptorids
preceptorids_id | bio_id  |  preceptors_status
----------------| ---------------------------
        1       |    5    |       3

bios
bio_id | bio_thana | boi_chaya  | bio_name  | bio_lastname | wat_stay
-------|-----------|------------|-----------|-------------------------
   5   |     8     |  chantha   |  harry    |   potter     |   7

wats
id |  wat_name   | district
---|-------------|------------
 7 |  watsothorn |  namuang

 thana
 thans_id | tname
 ---------| -----
      8   | Mr

status
status_id | preceptors
----------| -----
      3   | published

The controller for Assignment.add is as follows: which i will use it for select and save bio id to preceptorids //i am not sure that is this good way for laravel or not

$preceptor = DB::table('preceptorids')
            ->join('bios', 'preceptorids.bio_id', '=', 'bios.bio_id')
            ->join('wats', 'bios.bio_wat_stay', '=', 'wats.id')
            ->join('thana', 'bios.bio_thana', '=', 'thana.thana_id')
            ->select('bios.bio_wat_stay', 'thana.tname', 'bios.bio_chaya', 'bios.bio_name', 'bios.bio_lastname', 'wats.wat_name', 'wats.wat_district_id', 'wats.wat_amphurs_id', 'wats.wat_provinces_id','preceptorids.preceptors_status')
            ->where('preceptors_status', '=', 1)
            ->pluck('bio_chaya', 'preceptorids_id');

Expected Result : Frontend

tname  |  bio_name  | bio_chaya | bio_lastname  | wat_name   |  district  | preceptors_status | 
-------|------------|-----------|---------------|------------|------------|-------------------|
    Mr |   harry    |  chantha  |    potter     | watsothorn |   namuang  |   published       |

Expected Result : Backend

<select>
  <option value="1">Mr harry chantha potter watsothorn</option>
</select>

but when i dd($preceptor); it show only bio_chaya not preceptorids_id

Collection {#369 ▼
  #items: array:1 [▼
    "" => "chantha"
  ]
}

I'm new with laravel so any given guide will be so awesome.