Custom Query for fetching data from multiple tables in spring Data Jpa

Question

Entities are following

Product Table

@Entity
public class Product implements Serializable {
/*@Id
@GeneratedValue(strategy = Generation         


        

Answer 1

The way you are doing is not possible because you are assigning the result set to List but the query has some joins, it mean that the result of query is not a Product entity.

You can try to do a Native query. For example:

@PersistenceContext
private EntityManager entityManager;

public List customQuery(int id) {
    Query nativeQuery = entityManager.createNativeQuery(product_ordered).setParameter("id",id);
    return nativeQuery.getResultList();
}