Eclipselink NamedNativeQuery pass column name as parameter and not a value - eclipselink

Question

Trying to pass column name as parameter but JPA sets it as a value surrounding it with single quotes.
#NamedNativeQueries({
#NamedNativeQuery(
name = "Genre.findAllLocalized",
query = "SELECT "
+ " CASE "
+ " WHEN ? IS NULL THEN genre_default"
+ " ELSE ? "
+ " END localized_genre "
+ "FROM genre ORDER BY localized_genre")
})
Then:
List<String> res = em.createNamedQuery("Genre.findAllLocalized")
.setParameter(1, colName)
.setParameter(2, colName)
.getResultList();
The problem is that the column names being passed are taken as values so the result will return result list with repeated values of "col_name" instead of selecting the value of the column passed as parameter.
Is this achievable?

Answer 1

Basically it makes no sense to create a prepared query like this, how would you name that query anyway: "*"? So the short answer is: no.
But you could create named queries dynamically if this matches your requirement:
String colName = "colName";
String query = "SELECT WHEN " + colName + " IS NULL THEN genre_default";
Query query = entitymanager.createQuery(query);
Probably using a criteria builder is more the way you want to use JPA (code from https://en.wikibooks.org/wiki/Java_Persistence/Criteria):
// Select the employees and the mailing addresses that have the same address.
CriteriaBuilder criteriaBuilder = entityManager.getCriteriaBuilder();
CriteriaQuery criteriaQuery = criteriaBuilder.createQuery();
Root employee = criteriaQuery.from(Employee.class);
Root address = criteriaQuery.from(MailingAddress.class);
criteriaQuery.multiselect(employee, address);
criteriaQuery.where( criteriaBuilder.equal(employee.get("address"), address.get("address"));
Query query = entityManager.createQuery(criteriaQuery);
List<Object[]> result = query.getResultList();