Hi, I tried the criteria example from "NHibernate Reference Documentation" but I wasn't succesfull.

There's an exception: {"Failed to convert parameter value from a String to a Double."}

Do you have any ideas, what could be wrong???

Thanks!


CODE:

DetachedCriteria avgWeight = DetachedCriteria.For(typeof(Cat))
.SetProjection( Projections.Avg("Weight") );

session.CreateCriteria(typeof(Cat))
.Add( Subqueries.Gt("Weight", avgWeight) )
.List();


CLASS:
using System;
namespace MvNHibernateTest
{
public class Cat
{
private string id;
private string name;
private char sex;
private double weight;
public Cat()
{
}
public virtual string Id
{
get { return id; }
set { id = value; }
}
public virtual string Name
{
get { return name; }
set { name = value; }
}
public virtual char Sex
{
get { return sex; }
set { sex = value; }
}
public virtual double Weight
{
get { return weight; }
set { weight = value; }
}
}
}

MAPPING FILE:
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
namespace="MvNHibernateTest" assembly="MvNHibernateTest">
<class name="Cat" table="Cat">
<id name="Id">
<column name="CatId" sql-type="char(32)" not-null="true"/>
<generator class="uuid.hex" />
</id>

<property name="Name">
<column name="Name" length="16" not-null="true" />
</property>
<property name="Sex" />
<property name="Weight" />
</class>
</hibernate-mapping>

I add the complete exception:

The query and the subquery seem to be good...

Select * from Cat where ? in (subquery) .

The only problem is with "?"
If you replace it with "Weight", everythink is OK. But nhibernate doesn't do this.

HERE'S THE EXCEPTION

{"could not execute query\r\n[ SELECT this_.CatId as CatId0_0_, this_.Name as Name0_0_, this_.Sex as Sex0_0_, this_.Weight as Weight0_0_ FROM Cat this_ WHERE ? > (SELECT avg(this_0_.Weight) as y0_ FROM Cat this_0_) ]\r\nPositional parameters: 0 Weight\r\n[SQL: SELECT this_.CatId as CatId0_0_, this_.Name as Name0_0_, this_.Sex as Sex0_0_, this_.Weight as Weight0_0_ FROM Cat this_ WHERE ? > (SELECT avg(this_0_.Weight) as y0_ FROM Cat this_0_)]"}

SOLVED!!!

The problem is, that you must use Subqueries.PropertyGt insted of Subqueries.Gt

Watch out! There's an error in documentation!!!