左外連接的複雜NHibernate標準？

Question

我對NHibernate很新。我使用CreateSQLQuery編寫了這個代碼，但是如果可能的話我想把它移到NHibernate Criteria格式。我的查詢是這樣的：

select parent.ID as Id, ValueA.Total as ValueACount, ValueB.Total as ValueBCount 
from ParentTable parent 
left outer join 
(
    select count(*) as Total, ID 
    from ChildTable 
    where state = 'ValueA' 
    group by ID 
) ValueA on ValueA.ID = parent.ID 
left outer join 
(
    select count(*) as Total, ID 
    from ChildTable 
    where state = 'ValueB' 
    group by ID 
) ValueB on ValueB.ID = parent.ID 

我改變了表名/值來抽象一下。代碼按原樣運行，但這是我們在整個解決方案中唯一的查詢。我想看看我們是否可以擺脫它。

提前感謝所有可以幫助的人。如果你想給我一個能夠幫助我的非常好的網頁的鏈接，那也沒關係。我會至少大拇指:)

我也見過類似的問題。如果你覺得其他一些問題/答案會對我有很大的幫助，請隨時指出我的意見。

Answer 1

，你可以嘗試一些LINQ福

var results = from p in session.Query<Parent>() 
       select new 
       { 
        p.Id, 
        ValueACount = (from c1 in session.Query<Child>() where c1.State == "ValueA" && c1.Parent == p select c1).Count(), 
        ValueBCount = (from c2 in session.Query<Child>() where c2.State == "ValueB" && c2.Parent == p select c2).Count(), 
       }; 

或使用標準

var results = session.CreateCriteria<Parent>("p") 
    .SetProjection(Projections.ProjectionList() 
     .Add(Projections.Property("Id")) 
     .Add(Projections.SubQuery(DetachedCriteria.For<Child>() 
      .Add(Restrictions.Eq("State", "ValueA") && Restrictions.EqProperty("Parent", "p")) 
      .SetProjection(Projections.RowCount()))) 
     .Add(Projections.SubQuery(DetachedCriteria.For<Child>() 
      .Add(Restrictions.Eq("State", "ValueB") && Restrictions.EqProperty("Parent", "p")) 
      .SetProjection(Projections.RowCount())))) 
    .List();