I need to choose dynamically which parameters should be in query output. Is there any way to do something like that:
@Query(value = "select params = :arrayOfParams from myTable", nativeQuery = true)
User findparamsAll(@Param("arrayOfParams") List<String> params);
For example I have Entity User with name, surname, address, age. In one case I want to choose only name, in other sername, age and address. And e.t.c
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Answer
You can create interfaces to represent a View like the following:
public interface UserView {
String getName();
}
and then put it as the return value in your repository:
UserView findAll();
You can also implement a dynamic projection the following way:
T findAll(Class<T> type);
and call it like
userRepository.findAll(UserView.class) userRepository.findAll(User.class)
Read more about projection here: https://www.baeldung.com/spring-data-jpa-projections
Edit
You can be truely dynamic if you use javax.persistence.Tuple as return value in your interface:
Tuple findAll();
However you have to extract the data yourself then:
tuple.get("NAME", String.class)
However that still selects all fields from the database. If you truely want dynamic sql queries you can call EntityManager to create a dynamic SQL:
entityManager.createQuery("select ..."), Tuple.class).getResultList();
If you do that make sure to not be vulnerable for SQL injection!