Select latest record for each id spring jpa - spring

Question

I have an entity like this:
#Entity
class Point{
#EmbeddedId
private PointIdentity pointIdentity;
private float latitude;
private float longitude;
#Embeddable
public static class PointIdentity implements Serializable {
private Long id;
private ZonedDateTime timestamp;
}
}
There is EmbeddedId, so in "id" column can be multiple records with the same ids.
And I need to get latest record for each id, using CriteriaQuery and JPA specifications I think, but don't know how.
In SQL, this would be something like this:
SELECT id, MAX(timestamp)
FROM geodata
GROUP BY id
Is there any way to do it?
Any help, thanks.

Answer 1

You can easily write a JPQL query:
TypedQuery<Object[]> query = entityManager.createQuery(
"select p.pointIdentity.id, max(p.pointIdentity.timestamp) from Point p group by p.pointIdentity.id",
Object[].class);
List<Object[]> results = query.getResultList();
which translates to:
select
point0_.id as col_0_0_,
max(point0_.timestamp) as col_1_0_
from
point point0_
group by
point0_.id
Alternatively, you can use criteria query:
CriteriaBuilder criteriaBuilder = entityManager.getCriteriaBuilder();
CriteriaQuery<Object[]> query = criteriaBuilder.createQuery(Object[].class);
Root<Point> point = query.from(Point.class);
query.groupBy(point.get("pointIdentity").get("id"));
query.multiselect(
point.get("pointIdentity").get("id"),
criteriaBuilder.max(point.get("pointIdentity").get("timestamp"))
);
TypedQuery<Object[]> typedQuery = entityManager.createQuery(query);
List<Object[]> results = typedQuery.getResultList();
which produces identical SQL.