public IList<ColorGroup> GetDistinctColorGroups(int typeID, int finishID, string width)
            {
                string queryStr = "Select distinct c from ColorGroup c inner join c.Products p " +
                                  "where p.ShowOnline = 1 ";


                if (typeID > 0)
                    queryStr += " and p.ProductType.ID = " + typeID;

                if (finishID > 0)
                    queryStr += " and p.FinishGroup.ID = " + finishID;

                if (width != "")
                    queryStr += " and p.Size.Width = " + width;

                IList<ColorGroup> colors = NHibernateSession.CreateQuery(queryStr).List<ColorGroup>();

                return colors;
            }

<property name="Name" />

        <bag name="Products" generic="true" inverse="true" cascade="none">
            <key column="ColorGroupID" />
            <one-to-many class="...Domain.Product, ...Domain" />
        </bag>

<component name="Size" lazy="false" class="...Domain.Size, ...Domain">
            <property name="Width" />
            <property name="Length" />
            <property name="Thickness" />
        </component>

<many-to-one name="ProductType" class="...Domain.ProductType, ...Domain" column="ProductTypeID" not-null="true" ></many-to-one>
<many-to-one name="FinishGroup" class="...Domain.FinishGroup, ...Domain" column="FinishGroupID" not-null="true" ></many-to-one>

session.CreateQuery("select distinct c from ColorGroup c inner join c.Products p where p in (select p2 from Product p2 where p2.Size.Width=10)");