title: Unexpected sql statement in belongsTo Laravel relationship
body: <p>My <code>belongsTo</code> relationship has a following structure:</p>
  
  <pre><code>public function author() {
      return $this-&gt;belongsTo('App\User', 'author_id', 'id');
  }
  </code></pre>
  
  <p>And it produces the following query (when executing <code>$message-&gt;author()-&gt;getResults()-&gt;toSql()</code>):</p>
  
  <p><code>select * from "users" where "users"."id" is null and "users"."deleted_at" is null limit 1</code></p>
  
  <p><code>$message</code> does contain a valid <code>Message</code> instance, its <code>author_id</code> is set and a relevant <code>User</code> exists.</p>
  
  <p>Edit 1: As pointed out by @Jonas Staudenmeir my original code wasn't what I actually had in my code. The comments below hold, though, as I simply mismatched the params when typing out the question. I've edited the code to be an accurate representation of what's in the project.</p>
  
  <p>Edit 2: Included the Message model. The "attachments()" relation works fine, by the way.</p>
  
  <pre><code>class Message extends Model
  {
      use \Eloquent\Dialect\Json;
      use \Spatie\Macroable\Macroable;
      use SoftDeletes;
  
      /**
       * @var array
       */
      protected $guarded = [
          'id', 'created_at', 'updated_at', 'deleted_at',
      ];
  
      /**
       * @var array
       */
      protected $jsonColumns = [];
  
      public function author()
      {
          return $this-&gt;belongsTo('App\User', 'author_id', 'id');
      }
  
      public function attachments()
      {
          return $this-&gt;hasMany('App\File', 'file_id');
      }
  }
  </code></pre>