Fluent NHibernate - Query using Criteria with filter on connecting table - fluent-nhibernate

Question

I have following tables
User - Primary column - Id and other detail columns
Department - Primary column - Id and other detail columns
UserDepartment - Primary column - Id and other columns are UserId and DepartmentId
I want to find all users those are in department - (1 and 2).
I also want to find all users those are in department - (1 or 2).
Can anybody suggest me the criteria to get all users in department (1 and 2)? Another criteria to get all users in department - (1 or 2)?
I am new to FluentNHibernate, so didn't tried anything yet as I found nothing relevant on Google search? With the help of Google search, I was able to write criteria for 1-1 relations but not for above scenario.

Answer 1

assuming following classes
class User
{
public virtual int Id { get; private set; }
public virtual ICollection<Department> Departments { get; private set; }
}
class Department
{
public virtual int Id { get; private set; }
}
class UserMap : ClassMap<User>
{
public UserMap()
{
Id(x => x.Id);
HasManyToMany(x => x.Departments)
.Table("UserDepartment")
.ParentKeyColumn("UserId")
.ChildKeyColumn("DepartmentId");
}
}
then query for 1 or 2
var results = session.QueryOver<User>()
.JoinQueryOver<Department>(x => x.Departments)
.Where(d => d.Id.IsIn(departmentIds))
.List();
query for 1 and 2
User userAlias = null;
var subquery = session.QueryOver<Department>()
.Where(d => d.User.Id == userAlias.Id && d.Id.IsIn(departmentIds))
.Select(Projections.RowCount());
var results = session.QueryOver<User>()
.WithSubquery.WhereValue(departments.Count).Eq(subquery)
.List();