使用NHibernate Criteria的HAVING子句中的多个条件？

Question

我正在尝试使用NHibernate的Criteria API来编写相当于这个:

select foo_id from foo_history
group by foo_id
having sum(bar_in) > 0 or sum(baz_in) > 0;

使用此映射:

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" assembly="MVC"
                   namespace="MVC.Model.Things">
  <class name="MVC.Model.Things.FooHistory, MVC"
         table="foo_history">
    <id name="ID" column="foo_hist_id" type="guid"
        unsaved-value="00000000-0000-0000-0000-000000000000">
      <generator class="guid.comb" />
    </id>

    <!-- Properties -->
    <property name="BarIn" column="bar_in" type="decimal"
              precision="19" scale="4" not-null="true" />
    <property name="BazIn" column="baz_in" type="decimal"
              precision="19" scale="4" not-null="false" />

    <!-- Foreign Keys -->
    <many-to-one name="Foo" column="foo_id"
                 class="MVC.Model.Things.Foo, MVC.Model.Things"
                 not-null="true" />
  </class>
</hibernate-mapping>

和这个Criteria代码(分离,因为它将是一个子查询):

var results = DetachedCriteria.For<FooHistory>("fh")
    .SetProjection(Projections.ProjectionList()
        .Add(Projections.GroupProperty(Projections.Id()))
        .Add(Projections.Sum("fh.BarIn"))
        .Add(Projections.Sum("fh.BazIn")))
    .Add(Restrictions.Gt(Projections.Sum("fh.BarIn"), 0) ||
        Restrictions.Gt(Projections.Sum("fh.BazIn"), 0))
    .GetExecutableCriteria(session).List();

问题是SetProjection()在NHibernate生成无效MySQL 的结果之后添加条件限制:

SELECT this_.foo_hist_id as y0_,
       sum(this_.bar_in) as y1_,
       sum(this_.baz_in) as y2_
FROM foo_history this_
WHERE (sum(this_.bar_in) > ?p0
       or sum(this_.baz_in) > ?p1)
GROUP BY this_.foo_hist_id

...使用WHERE而不是HAVING.使用单个限制工作正常,一切都是正确的.我假设自从HN-1280("添加对CreateCriteria查询的支持,修复参数顺序错误")这是可能的,但我没有使用正确的"OR"语言(例如,Restrictions.Disjunction()总是创建WHERE).

这可能吗？

Answer 1

我遇到了这个问题，但是我不认为我的解决方法很好，因为它不起作用，例如当您需要 ToRowCountQuery() 进行分页时。但无论如何...您可以使用此类而不是内置的 OrExpression

class OrHaving : OrExpression
    {
        public OrHaving(ICriterion lhs, ICriterion rhs) : base(lhs, rhs)
        {
        }

        public override IProjection[] GetProjections()
        {
            return LeftHandSide.GetProjections().Concat(RightHandSide.GetProjections()).ToArray();
        }
    }

喜欢

.Add(new OrHaving (Restrictions.Gt(Projections.Sum("fh.BarIn"), 0) ,
                   Restrictions.Gt(Projections.Sum("fh.BazIn"), 0)))