SELECT в PostgreSQL: Can't cast database type record to Int32

 public string Request()
        {
            string request = $"SELECT (worker_id, first_name, last_name, workers.department_id) " +
                $"FROM workers ";
            return request;
        }

 public string Request()
        {
            string request = $"SELECT * FROM workers ";
            return request;
        }

SELECT (worker_id, first_name, last_name, workers.department_id)

  void Select_All()
            {
                if(request.GetType() == new Select_All().GetType())
                {
                List<Worker> list = new List<Worker>();
                using (var reader = cmd.ExecuteReader())
                {
                    while (reader.Read())
                    {
 
                            Console.WriteLine("{0} {1} {2} {3} ", reader.GetInt32(0), reader.GetString(1),
                           reader.GetString(2), reader.GetInt32(4));
 
                            //worker.Worker_id = reader.GetInt32(0);
                            //worker.First_Name = reader.GetString(1);
                            //worker.Last_Name = reader.GetString(2);
                            //worker.Depatment_id = reader.GetInt32(3);
                            //worker.Depatment_parent_id = reader.GetInt32(4);
                            //worker.Salary = reader.GetInt32(4);
                            //worker.Type_Worker = reader.GetString(5);
                            //list.Add(worker);
                        }
                }

if(request.GetType() == typeof(Select_All))

public class Search : Columns, IRequest
    {
        public string Request()
        {
            string request = $"SELECT  department_id  FROM department" +
                $"WHERE department_id = {Depatment_id}";
 
            return request;
        }
    }

var user  = db.Query<User>("SELECT * FROM Users WHERE Id = @id", new { id }).FirstOrDefault();