Hibernate count rows with some criterias

Question

Suppose I have a table Person and i want to count all those people whose \"birthDate\" is not null and they are a student. Assuming i have two columns :

birthDat         


        

Answer 1

Criteria crit = session.createCriteria(Person.class);
crit.add( Restrictions.isNotNull("birthDate"));
crit.add( Restrictions.eq("isStudent", true));
List students = crit.list();
Integer count = students.size();

or if just want a single count value, and no list returned :

Criteria crit = session.createCriteria(Person.class);
crit.setProjection(Projections.rowCount());
crit.add( Restrictions.isNotNull("birthDate"));
crit.add( Restrictions.eq("isStudent", true));
return (Long) crit.uniqueResult();