Hibernate forming the wrong query it seems

Question

My requirement is to extract all the distinct rows(name column alone) where name is not null This is my hibernate code.

DetachedCriteria criteria = DetachedCriteria.forClass(A.class);
criteria.add(Restrictions.isNotNull("name"));
ProjectionList list = Projections.projectionList();
list.add(Projections.distinct(Projections.property("name")),"name");
criteria.setProjection(list);
criteria.setResultTransformer(Transformers.aliasToBean(A.class));
result = getHibernateTemplate().findByCriteria(criteria);

The SQL formed is below:

select distinct this_.name as y0_ 
from dbo.A this_ 
where y0_ is not null 

The error is ERROR - Invalid column name 'y0_' I dont understand why hibernate is forming the wrong query like this. Any help appreciated.

Code for class A:

@Entity
@Table(name = "A", uniqueConstraints = {})
public class A implements java.io.Serializable {

    private int skillId;
    private String name;

    public A() {
    }

    @Id
    @Column(name = "SKILL_ID", unique = true, nullable = false, insertable = true, updatable = true)
    @GeneratedValue(strategy = GenerationType.AUTO)
    public int getSkillId() {
        return this.skillId;
    }

    public void setSkillId(int skillId) {
        this.skillId = skillId;
    }

    }

    @Column(name = "name", unique = false, nullable = true, insertable = true, updatable = true, length = 100)
    public String getName() {
        return this.name;
    }

    public void setName(String name) {
        this.name = name;
    }

}

Answer 1

Try this

DetachedCriteria criteria = DetachedCriteria.forClass(A.class);
criteria.add(Restrictions.isNotNull("name"));
ProjectionList list = Projections.projectionList();
list.add(Projections.property("name"));
criteria.setProjection(Projections.distinct(list));

Answer 2

Try out following:

Criteria criteria = session.createCriteria(Test.class);
ProjectionList projectionList = Projections.projectionList();
ProjectionList projectionList2 = Projections.projectionList();
projectionList2.add(Projections.distinct(projectionList.add(Projections.property("distinctColumn"), "distinctColumn")));
projectionList2.add(Projections.property("col1"), "col1");
projectionList2.add(Projections.property("col2"), "col2");
criteria.setProjection(projectionList2);
criteria.setResultTransformer(Transformers.aliasToBean(Test.class)); 
List list = criteria.list();

In you case, "distinctColumn" will be "name".

Answer 3

we had the same problem, Creating an alias solved the issue, try:

Criteria criteria = session.createCriteria(A.class, "a")
criteria.add(Restrictions.isNotNull("a.name"));
ProjectionList list = Projections.projectionList();
list.add(Projections.distinct(Projections.property("a.name")),"name");
criteria.setProjection(list);
criteria.setResultTransformer(Transformers.aliasToBean(A.class));
result = getHibernateTemplate().findByCriteria(criteria);