Nhibernate GroupBy 多个和计数

Question

首先我知道 GroubBy 的多个属性尚未实现。

我想做的是，

SELECT count(*)
FROM ( 
    SELECT this_.SubmissionDate as y0_
    FROM   [Coupon] this_
    WHERE  this_.PaymentOrder_id is null 
    GROUP BY this_.SubmissionDate,
           this_.Deal_id
) AS query

我在 Nhibernate 中拥有的最好的功能是

Session.QueryOver<Coupon>().Select(Projections.Group<Coupon>(e => e.SubmissionDate),Projections.Group<Coupon>(e => e.Deal.Id)).Future<object[]>().Count()

带来整个集合，然后对其进行计数。

我找到了这个并创建了

var count = Session.CreateQuery("select count(*) from (select c.SubmissionDate from Coupon c where c.PaymentOrder.Id is null group by c.SubmissionDate, c.Deal.Id) as query").FutureValue<Int32>();

这个不起作用。抛出

Exception of type 'Antlr.Runtime.NoViableAltException' was thrown. near line 1, column 21

Exception Details: NHibernate.Hql.Ast.ANTLR.QuerySyntaxException: Exception of type 'Antlr.Runtime.NoViableAltException' was thrown. near line 1, column 21

更多异常

[QuerySyntaxException: Exception of type 'Antlr.Runtime.NoViableAltException' was thrown. near line 1, column 21]
   NHibernate.Hql.Ast.ANTLR.ErrorCounter.ThrowQueryException() +118
   NHibernate.Hql.Ast.ANTLR.HqlParseEngine.Parse() +416

Answer 1

您是否尝试过这样的事情，它将在内存中进行计数？

var count = Session.CreateQuery("select c.SubmissionDate from Coupon c where c.PaymentOrder.Id is null group by c.SubmissionDate, c.Deal.Id").ToList().Count;

HQL 似乎不支持 select 和 where 之外的子查询： http://docs.jboss.org/hibernate/core/3.3/reference/en/html/queryhql.html#queryhql-subqueries

否则，您可以创建一个存储过程，并将其添加到您的映射：正确的 NHibernate 映射存储过程？