title: Laravel Datatables search on nested Relationship
body: <p>I'm currently using datatabels 7.0 and Laravel 5.4
  data in my grid is showing correctly but when I want to search on nested relationship column I got below error:</p>
  
  <pre><code>SQLSTATE[42S22]: Column not found: 1054 Unknown column 'course_semester.semester.name' in 'where clause' (SQL: select count(*) as aggregate from (select '1' as `row_count` from `videos` where LOWER(`videos`.`id`) LIKE %%te%% and LOWER(`videos`.`name`) LIKE %%te%% and LOWER(`course_semester`.`semester`.`name`) LIKE %%te%%) count_row_table)
  </code></pre>
  
  <p>Here is my code</p>
  
  <p>Controller</p>
  
  <pre><code>$videos = Video::with(['course_semester' =&gt; function ($query) {
              return $query-&gt;with('course', 'semester');
          }])-&gt;select('videos.*');
          return Datatables::of($videos)
                  -&gt;addColumn('check', '&lt;input type="checkbox" name="selected-videos" value="{{$id}}"&gt;')
                  -&gt;escapeColumns([])
                  -&gt;make(true);
  </code></pre>
  
  <p>Javascript</p>
  
  <pre><code>columns: [
                   { data: 'check' , name: 'check',orderable: false, searchable: false },
                   { data: 'id', name: 'videos.id' },
                   { data: 'name', name: 'videos.name' },
                   { data: 'course_semester.semester.name', name: 'course_semester.semester.name'},
                   { data: 'course_semester.course.name', name: 'course_semester.course.name'},
                   { data: 'status', name: 'videos.status' },
                   { data: 'comment', name: 'videos.comment' },
                   { data: 'video_date', name: 'videos.video_date' },
              ]
  </code></pre>
  
  <p>Can anyone help me and notice my problem?</p>
  
  <p>Thanks in advance.</p>