<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
    namespace="MyNamespace" assembly="MyAssembly">

    <class name="Event" table="Event">

        <id name="Id" unsaved-value="-9999">
            <column name="EvtId" sql-type="Int32" not-null="true" />
            <generator class="increment" />
        </id>

      <version name="VersionNumber" column="EvtVersionNo" type="Int32" access="property" />
       
        <property name="TypeCode" column="EvtTypeCd" />
        <property name="StartDateTime" column="EvtStartDateTime" />
        <property name="EndDateTime" column="EvtEndDateTime" />
        <property name="Deleted" column="EvtDeleteFl" />   
       
         <joined-subclass name="TrainingEvent" table="TrainingEvent">
         <key column="EvtId"/>
            <property name="Name" column="TevName"/>
            <property name="NullableTrainingProviderId" column="TpvId" type="Nullables.NHibernate.NullableInt32Type, Nullables.NHibernate" />
         <property name="NullableLocation" column="TevLocation" />
         <property name="Completed" column="TevCompleteFl"/>
         <property name="TrainingCoursesAreRefreshers" column="TevCoursesAreRefreshers"/>
         
            <set name="TrainingCourseIds" table="TrainingEventCourse">
            <key column="EvtId"/>
            <element column="TcrId" type="Int32"/>
         </set>
         
         <set name="EmployeeIds" table="TrainingEventEmployee">
            <key column="EvtId"/>
            <element column="EmpId" type="Int32"/>
         </set>

      </joined-subclass> 
         
    </class>

</hibernate-mapping>

string sql = "from TrainingEvent tev, Event evt where ( "
                         + " (:startDateTime < evt.StartDateTime AND :endDateTime > evt.EndDateTime) "
                         + " OR (:startDateTime BETWEEN evt.StartDateTime AND evt.EndDateTime) "
                         + " OR (:endDateTime BETWEEN evt.StartDateTime AND evt.EndDateTime) "
                         + " ) AND tev.Id = evt.Id ";
         
IQuery query = mySessionCreateQuery(sql);
query.SetDateTime("startDateTime", startDateTime);
query.SetDateTime("endDateTime", endDateTime);
IList results = query.List();