title: How make doctrine findby to json field without native query
body: <p>I use <code>json</code> column in <code>doctrine 2</code> (In <code>MySQL</code> database).
  Actually, I made my search in <code>json</code> with native query like</p>
  
  <pre><code>$rsm = new ResultSetMappingBuilder($entityManager);
  $rsm-&gt;addRootEntityFromClassMetadata(\blabla\MyObject::class, 'o');
  $query = $entityManager-&gt;createNativeQuery('select o.* from my_objects o where json_extract(jsonData, "$.test.key1")= "value1"', $rsm); 
  //jsonData column contains {"test": {"key1" : "value1"}}
  $result = $query-&gt;getResult();
  </code></pre>
  
  <p>Is it possible the made query like that without the native query mechanism ?
  (like a findBy)</p>
  
  <p>Thanks in advance for your help ;)</p>