Laravel Datatables search on nested Relationship

Because of using select() here, you do not load the relationship. Also, use dot syntax for nested eager loading:

$videos = Video::with(['course_semester', 'course_semester.course'])

1- dataTable function

public function dataTable($query){    return datatables()        ->eloquent($query)        ->addColumn('BulkSelection', function ($category)         {        ->addColumn('company', function ($category)         {            return $category->company ? $category->company->name : 'No Company';        })        ->rawColumns(['action', 'company', 'createdAt','BulkSelection']);}

2- query function

    public function query(Category $model){        return $model->with('company:id,name')->select('categories.*')->newQuery();}

3- getColumns function

$getCols = [             'id',        'name',        'company'=> [            'data'=>'company',            'name'=>'company.name'        ],        'createdAt' => [            'name'=>'created_at',            'searchable' => false        ],        'action' => [            'exportable' => false,            'searchable'=>false,            'orderable' => false        ]    ];    return $getCols;

If you just need to load the data from relation tables, use the below code

$videos = Video::with('course_semester','course', 'semester')->select('videos.*');        return Datatables::eloquent($videos)                ->addColumn('check', function(Video $v){                   return '<input type="checkbox" name="selected-videos" value="{{$v->id}}">'                  })                ->rawColumns(['check'])                ->make(true);

And in script, you can call relation values as ,

          {data: 'course_semester.id'},          {data: 'course.name'},          {data: 'semester.name'},