QueryOver restriction using an alias

Adding a restriction on a where clause from an alias can be tricky to understand using QueryOver. The SQL we are trying to achieve is:-

from projects p
inner  join user u on p.UserId = u.UserId
where m.UserId = 100 or p.OwnerId = 100

Our goal is to achieve the following:-

• We have a project that has a owner and a list of managers.
• Both managers and owners are users
• We want to get all projects for a user that they are the owner OR the manager
• We want to use QueryOver
  

The domain:-

public class User {
    long Id;
    string Name;
}

public class Project {
    long Id;
    User Owner;
    IList<User> Managers;
}

The query is built like this:-

User manager = null;

var query = session
  .QueryOver<Project>()
  .JoinAlias(j => j.Managers, () => manager)
  .Where(w => manager.Id == user1.Id || w.Owner.Id == user1.Id)
  .List<Project>();

The above query joins Project to Managers using an alias manager. This allows us to then use the alias manager in the where statement e.g.

.Where(w => manager.Id == user1.Id || w.Owner.Id == user1.Id)

This works correctly but could have a small glitch. What happens if our domain contains a user that is a owner BUT is not a manager? The problem is the SQL will be created using an inner join. This problem can be fixed by simply adding a LEFT join to the query.

.JoinAlias(j => j.Managers, () => manager).Left

It should be noted that this was an answer I gave to a recent StackOverFlow question.