如何加入 laravel 关系

Question

I want to write a sort class for spatie query builder but my problem is I have 3 models hotel room and discount so now hotel has many rooms and rooms has many discounts I want to sort the hotels by the lowest discount available on rooms so now here is the query I tried note that $query is loading all the hotels:

$data = $query->with('accommodationRoom')
            ->join('discounts','accommodation_rooms.id','=','discounts.accommodation_room_id')
            ->get();

but I get this error:

message: "SQLSTATE[42S22]: Column not found: 1054 Unknown column 'accommodation_rooms.id' in 'on clause' (SQL: select * from accommodations inner join discounts on accommodation_rooms . id = discounts . accommodation_room_id where exists (select * from accommodation_rooms where accommodations . id = accommodation_rooms . accommodation_id and bed_count = 5))",

its because I am loading a relation to a join but that does not recognizing the filed.

Answer 1

Use multiple join statements..

    $data = DB::table('accommodation_rooms')
       ->join('hotels','accommodation_rooms.id','=','hotels.room_id') // replace room_id with your column name
       ->join('discounts','accommodation_rooms.id','=','discounts.accommodation_room_id')
       ->select('accommodation_rooms.*','hotels.*','discounts.*')
       ->get();

Answer 2

Add Relation in Model files.

Hotel Model

Class Hotel{

    public function room()
    {
        return $this->hasMany(Room::class,'hotel_id','id');
    }
}

Room Model

Class Room{

    public function discount()
    {
        return $this->hasMany(Discount::class,'room_id','id');
    }
}

Record Fetch Query

$data = Hotel::with('room', 'room.discount')->orderBy('room.discount.value', 'ASC')->get();

Change your model and field name in the above code.

Answer 3

You should join with accommodationRoom too.

You can even join to multiple tables in a single query:

$data = $query->join('accommodation_rooms','hotels.id','=','accommodation_rooms.hotel_id')
    ->join('discounts','accommodation_rooms.id','=','discounts.accommodation_room_id')
    ->select('hotels.*', 'discounts.*')
    ->orderBy('discounts.value')
    ->get();

See Joins .