Hibernate Max() Function (Aggregate Functions)


In this section, we will show you, how to use the Max() function. Hibernate supports multiple aggregate functions. When they are used in HQL queries, they return an aggregate value ( such as avg(...), sum(...), min(...), max(...) , count(*), count(...), count(distinct ...), count(all...) ) calculated from property values of all objects satisfying other query criteria. 
Following is a aggregate function (max() function) with their respective syntax.
max( [ distinct | all ] object.property)
The Max() function aggregates the maximum value of the given column. 
Table Name: insurance
ID
insurance_name
invested_amount
investement_date
2
Life Insurance
25000
0000-00-00 00:00:00
1
Givan Dhara
20000 
2007-07-30 17:29:05
3
Life Insurance
 500
2005-10-15 00:00:00
4
Car Insurance 
 2500
2005-01-01 00:00:00
5
Dental Insurance
500
2004-01-01 00:00:00
6 
Life Insurance
900
2003-01-01 00:00:00
7 
Travel Insurance
 2000 
2005-02-02 00:00:00
Here is the java code to retrieve the maximum value of "invested_amount" column from insurance table:
package roseindia.tutorial.hibernate;

import java.util.Iterator;
import java.util.List;

import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;

public class HibernateHQLMaxFunction {

  /**
 * mail_mevinod@yahoo.co.in
 */
  public static void main(String[] args) {
  // TODO Auto-generated method stub

  Session sess = null;
  try {
  SessionFactory fact = new 
Configuration().configure().buildSessionFactory();
  sess = fact.openSession();
  String SQL_QUERY = "select 
max(investementAmount)from Insurance insurance";
  Query query = sess.createQuery(SQL_QUERY);
  List list = query.list();
  System.out.println("Max 
Invested Amount: " + list.get(0)); 
  sess.close();
  }
  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 max(insurance0_.invested_amount) as col_0_0_ from insurance insurance0_
Max Invested Amount: 25000

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