@Entity
public class Sku {
  @Id
  private Long id;
  @Embeddable
  private Summary summary = new Summary();
}

@Embeddable
public class Summary {
  @Column(name = "CREATED_BY")
  private String createdBy;
}

em.createQuery("select s from Sku s where s.summary.createdBy = ?1").setParameter(1, param).getResultList();

List<Number> ids = em.createNativeQuery("select id from sku where created_by = ?1").setParameter(1, param).getResultList();
for (Number id : ids) {
  skus.add(em.find(Sku.class, id.longValue()));
}