title: Select objects without some properties in Symfony 3.4
body: <p>I have one problem in Symfony that I cannot solve.
  I have one Entity class e.g. Category where I have e.g. $id, $name, $description, OneToMany User[] $members, OneToMany Book[] $books
  Now... I need to get all categories (e.g. WHERE description IS NOT NULL) but in results, I don't want to have $books.<br />
  I need Category with id, name, description and [member1, member2...] but <strong>NO</strong> books.
  I use something like:</p>
  <pre><code>$em-&gt;getRepository('AppBundle:Category')-&gt;findAll();
  </code></pre>