Question

Given the following domain model:

Dog { Id, Name, Color }

Color { Id, Name }

How do I get the Colors for which there are dogs with NHibernate.Linq. In SQL I would

SELECT Color.Id, Color.Name FROM Color 
    WHERE Id IN 
    (SELECT DISTINCT Dog.ColorId FROM Dog);

Answer 1

This might work:

Colors.Where(c => Dogs.Any(d => d.Color.Equals(c)))

However if you are matching purely on the color identifier, try this instead:

Colors.Where(c => Dogs.Any(d => d.Color.Id == c.Id))

These will give you all of the colors which are used by the dogs.