In this section, you will learn to hibernate aggregate function like: sum() using hibernate projection.

Hibernate Projection Example (Sum)

In this section, you will learn to hibernate aggregate function like: sum() using hibernate projection. 
The following example to calculate the sum of invested_amount to the Insurance table 
Table Name: Insurance


Here is the code of program:

package roseindia.tutorial.hibernate; import java.util.List; import org.hibernate.Criteria; import org.hibernate.Session; import org.hibernate.SessionFactory; import org.hibernate.cfg.Configuration; import org.hibernate.criterion.ProjectionList; import org.hibernate.criterion.Projections; public class ProjectionExample1 {   /**  * @param args  */   public static void main(String[] args) {   // TODO Auto-generated method stub      Session sess = null;   try {   SessionFactory fact = new   Configuration().configure().buildSessionFactory();   sess = fact.openSession();   Criteria crit = sess.createCriteria(Insurance.class);   ProjectionList proList = Projections.projectionList();   proList.add(Projections.sum("investementAmount"));   crit.setProjection(proList);   List sumResult = crit.list();   System.out.println("Total Invested Amount: " + sumResult);   }   catch(Exception e){   System.out.println(e.getMessage());   }   } }

Output:

log4j:WARN No appenders could be found for logger (org.hibernate.cfg.Environment).log4j:WARN Please initialize the log4j system properly.Hibernate: select sum(this_.invested_amount) as y0_ from insurance this_ Total Invested Amount: [51400]