Critérios de hibernação

esta pergunta é sobre o uso do Hibernato Criteria para fazer um group by.
Aqui está o meu SQL:

SELECT s.name, max(p.price), min(p.price)
FROM supplier s, product p
WHERE s.supplier_id = p.supplier_id
GROUP BY s.name

tentei o seguinte:

Criteria criteria = session.createCriteria(Supplier.class); 

Criteria prodCrit = criteria.createCriteria("products"); 

ProjectionList projList = Projections.projectionList(); 
projList.add(Projections.max("price"));
projList.add(Projections.min("price")); 
projList.add(Projections.groupProperty("name"));
prodCrit.setProjection(projList);
List list = criteria.list();

mas eu tenho o seguinte erro:

Exception in thread "main" org.hibernate.QueryException: could not resolve property: price of: com.gtc.hibernate.query.Supplier
Author: Nathaniel Ford, 2012-12-21

1 answers

Tente createAlias em vez de createCriteria. Irá produzir uma consulta SQL.

select 
       max(p1_.price) as y0_, 
       min(p1_.price) as y1_, 
       this_.name as y2_ 
from Supplier this_ 
   inner join Product p1_ on this_.id=p1_.supplier_id 
 group by this_.name;

Critérios:

Criteria criteria = session.createCriteria(Supplier.class); 
criteria.createAlias("products","p");

ProjectionList projList = Projections.projectionList(); 
projList.add(Projections.max("p.price"));
projList.add(Projections.min("p.price")); 
projList.add(Projections.groupProperty("name"));
criteria.setProjection(projList);
List list = criteria.list();
 3
Author: Manuel Quinones, 2012-12-21 21:24:49