Many to many with outer join and dapper

I have three tables

• Users (id, firstname, lastname)
• Modules (id, name)
• Users_modules (id, u_id, m_id, secret, token) (many-to-many. Represents modules that are authorized for users)

What would be the query to get the following data back for a specific user:

• User (id, firstname, lastname)
• Authorized modules (id, 1 as isAuthorized) from users_modules
• Unauthorized modules (id, 0 as isAuthorized) outer join with modules

for the sake of me, couldn't figure this out. This is my try:

Select u.firstName, u.lastName, u.id, m.id,m.name
From modules m
Left Outer Join users_modules uc On uc.m_id = m.id
Left Outer Join users u On
    u.id = uc.u_id And
    u.id = 120

Then I want to map the results back to my User class using dapper so that user object will have all modules authorized and unauthorized in Modules list property

public class User
    {
        public int Id { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public List<Module> Modules{ get; set; }

        public User()
        {
            Modules= new List<Module>();
        }
    }

[Table("modules")]
    public class Module
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public string AuthorizationBaseUri { get; set; }
        public bool IsAuthorized { get; set; }
        public string LoginUrl { get; set; }

        public Module()
        {
            LoginUrl = string.Empty;
            AuthorizationBaseUri = string.Empty;
            IsAuthorized = false;
        }
    }

I had to get the authorized modules for a user first (using dapper multiple mapping), then get all modules, and then finally do the subtraction manually at my business layer. I know there is a smarter way to do it, yet to find out.