混合的投影

Question

I am trying to get the distinct on my column "testType" in table "Test". Also I want to get both "testType" and "testId" in my list. For that I am doing this but it doesn't applying the distinct , giving me the duplicate result.

Any idea how can I resolve this?

Session session = sessionFactory.openSession();
Criteria crit = session.createCriteria(Test.class);
ProjectionList proList = Projections.projectionList();
proList.add(Projections.property("testType"));
proList.add(Projections.property("testId"));
crit.setProjection(proList);
crit.setResultTransformer(Criteria.DISTINCT_ROOT_ENTITY);
List rsList = crit.list();

Thanks in advance.

Answer 1

to get the distinct values of testType

Session session = sessionFactory.openSession();
List results = session.createCriteria(Test.class);
    .setProjection(Projections.distinct(Projections.property("testType")))
    .list();

but to get the id as well you can't select for it since there may be many ids for each Type, eg:

testId | testType
-----------------
1      | type1
2      | type2
3      | type1
4      | type2
6      | type3
7      | type3

what should Select Distinct(testType), testid return?

1. (type1, 1), (type2, 2), (type3, 6)
2. (type1, 3), (type2, 4), (type3, 7)
3. (type1, 1), (type2, 4), (type3, 6)

1)

Session session = sessionFactory.openSession();
List results = session.createCriteria(Test.class);
    .setProjection(Projections.projectionList()
        .add(Projections.group(Projections.property("testType"))))
        .add(Projections.Min(Projections.property("testid")))))
    .list();

2)

Session session = sessionFactory.openSession();
List results = session.createCriteria(Test.class);
    .setProjection(Projections.projectionList()
        .add(Projections.group(Projections.property("testType"))))
        .add(Projections.Max(Projections.property("testid")))))
    .list();