code: public R fetchQuery(String path, String properties) {
      query.fetchQuery(path, properties);
      return root;
    }
docs: Specify a path and properties to load using a "query join".
  
  <pre>{@code
  
  List<Customer> customers =
  new QCustomer()
  // eager fetch contacts using a "query join"
  .fetchQuery("contacts", "email, firstName, lastName")
  .findList();
  
  }</pre>
  
  @param path the property path of an associated (OneToOne, OneToMany, ManyToOne or ManyToMany) bean.