title: Laravel relationship Column 'id' in where clause is ambiguous
body: <p>I have courses and subscription types.
  I want to get all the courses that has a given subscription type.
  My attempt:</p>
  <pre><code>$courses=Course::wherehas('subscriptionType',function ($q)
          {
              return $q-&gt;where('id','1');
          })-&gt;get();
  </code></pre>
  <p>But this fails:</p>
  <blockquote>
  <p>Column 'id' in where clause is ambiguous</p>
  </blockquote>
  <p>Any tips on doing this?</p>