title: Laravel not updating null values to column
body: <p>Migration </p>
  
  <pre><code>Schema::create('users', function (Blueprint $table) {
          $table-&gt;increments('user_id');
          $table-&gt;string('username',50)-&gt;unique();
          $table-&gt;date('start_date');
          $table-&gt;date('end_date')-&gt;nullable();
          $table-&gt;timestamps();
      });
  </code></pre>
  
  <p>Here start_date set as column type date and nullable</p>
  
  <p>When running Insert function like below its inserting null values</p>
  
  <pre><code>$insert = [
      'username'  =&gt;strtoupper(request('username')),
      'password'  =&gt;Hash::make(request('password')),
      'start_date'  =&gt;date('Y-m-d',strtotime(request('start_date'))),
    ];
    if(request()-&gt;filled('end_date')){
      $insert['end_date'] = date('Y-m-d',strtotime(request('end_date')));
    }
    User::create($insert);
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/ghXl6.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ghXl6.png" alt="enter image description here"></a></p>
  
  <p>When Updating the same row left blank as end_date input,</p>
  
  <pre><code>$user = User::GetWithEncrypted(request('user_id'));
  $update ['start_date'] = date('Y-m-d',strtotime(request('start_date')));
  if(request()-&gt;filled('end_date')){
    $update['end_date'] = date('Y-m-d',strtotime(request('end_date')));
  }else{
    $update['end_date'] = 'NULL';
  }
  $user-&gt;update($update);
  </code></pre>
  
  <p>In Table, it comes like below
  <a href="https://i.stack.imgur.com/qyEHA.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/qyEHA.png" alt="enter image description here"></a></p>
  
  <p>How can I make it NULL like insert function in update? 
  My strict mode is false now, If I make it true it will throw an exception of invalid data for the end_date column.</p>