JPA SQL select and sum from entity manager - mysql

Question

The following SQL script works in mysql:
select
LOGGING_ID,
SUM(NORMAL_HOURS +OVERTIME_HOURS +DOUBLE_TIME_HOURS) AS TOTAL_HOURS
FROM
LOGGING_DETAIL
GROUP BY 1
How would I do this with my entity manager?:
#PersistenceContext
private EntityManager database;
List<loggingDetail> loggingDetail = new ArrayList<loggingDetail>();
timeLoggingDetail = database.createQuery("").getResultList();
at the end I want the Logging_id and the total hours for that ID.
Thanks

Answer 1

The entity manager could called a named query that you set on your jpa entity object. I am assuming you have an entity object in this case. I suppose if you don't have that object you could do it in the query like you have it laid out in your question. I like having it in the entity object though so other calls can re-use it.
Entity object -
#Entity
#NamedQuery( name = "loggingDetail.getLoggingId", query = "select
LOGGING_ID,SUM(NORMAL_HOURS +OVERTIME_HOURS +DOUBLE_TIME_HOURS) AS TOTAL_HOURS
FROM LOGGING_DETAIL GROUP BY 1" )
public class LoggingDetail
{ ...}
The entity manager call will not get a fully populated loggingDetail object back since the query is not returning a full object, so you have to loop through an object array -
#PersistenceContext
private EntityManager database;
Query query = database.createNamedQuery( "loggingDetail.getLoggingId" );
List<Object[]> obj = query.getResultList();
for( Object[] objects : obj )
{
String logId = (String) objects[0] ;
String logTime = (String) objects[1] ;
}