NHibernate QueryOver with subquery and alias

Question

I am trying to convert the following (simplified) HQL to QueryOver:

select subscription from Subscription as subscription where not exists ( from Shipment as shipment where shipment.Subscription = subscription and (shipment.DeliveryDate = :deliveryDate) ) 

I went so far:

 Subscription subscription = null; Session.QueryOver(() => subscription) .Where(Subqueries.NotExists(QueryOver.Of<Shipment>() .Where(shipment => shipment.Subscription == subscription) .And(shipment=> shipment.DeliveryDate == deliveryDate) .Select(shipment => shipment.Id).DetachedCriteria)); .TransformUsing(new DistinctRootEntityResultTransformer()); 

The problem is that the above Subqueries and Where statements provide me with the following (invalid) where clause:

 where shipment.SubscriptionId is null 

when I want:

 where shipment.SubscriptionId = subscription.Id 

Thus, the alias and its row level value are not taken into account when building SQL; instead, its initial null value is used to compare with the Shipment SubscriptionId .

Update

Using the solution provided by dotjoe, I was able to write the QueryOver as follows:

 Subscription subscription = null; Session.QueryOver(() => subscription) .WithSubquery.WhereNotExists(QueryOver.Of<Shipment>() .Where(shipment => shipment.Subscription.Id == subscription.Id) .And(shipment => shipment.DeliveryDate == deliveryDate) .Select(shipment => shipment.Id)); 

Answer 1

to try

 .Where(shipment => shipment.Subscription.Id == subscription.Id)