How to hide unwanted fields in JSON response using Dapper?

Question

ASP.NET

I am writing a REST API server on ASP.NET Core 2.1. I want to use Dapper as ORM. Previously, he developed only small desktop projects for working with the database.
There is a class corresponding to a table in the database:

public class User
    {
        public int id { get; set; }
        public string FIO { get; set; }
        public int age { get; set; }
        public string city { get; set; }
        public string somedata1 { get; set; }
        public string somedata2 { get; set; }
        public string somedata3 { get; set; }
    }

Interface:

public interface IUser
        {
            IEnumerable<User> GetUsers();
            IEnumerable<User> GetSomeData1();
            IEnumerable<User> GetSomeData2();
        }

The class that implements it:

public class UserRepository : IUser
    {
        /* ... */

        public IEnumerable<User> GetUsers()
        {
            using (IDbConnection connection = GetConnection())
            {
                return connection.Query<User>("select id, fio, age, city, somedata1, somedata2, somedata3 from users");
            }
        }
    }

In the controller class I use the method from the UserRepository:

[HttpGet]
        public IEnumerable<User> GetUsers()
        {
            return _userRepository.GetUsers();
        }

I get something like this JSON response:

[{"id":1, "fio":"Иванов И. И.", "age":10, "city":"dc", "somedata1":"data1", "somedata2":"data2", "somedata3":"data3"}]

Good. How can I now implement the GetSomeData1() method so that only those table fields that I select in the query are returned in JSON? Why not create several variations of the entity class from the base for each method?
For example, to code:

public IEnumerable<User> GetSomeData1()
        {
            using (IDbConnection connection = GetConnection())
            {
                return connection.Query<User>("select id, fio, somedata3 from users where id in (1,2)");
            }
        }

returned

[{"id":1, "fio":"Иванов И. И.", "somedata3":"data3"},
{"id":2, "fio":"Петров А. А.", "somedata3":null}]

instead of

[{"id":1, "fio":"Иванов И. И.", "age":null, "city":null, "somedata1":null, "somedata2":null, "somedata3":"data3"},
{"id":2, "fio":"Петров А. А.", "age":null, "city":null, "somedata1":null, "somedata2":null, "somedata3":null}]

Found a variant using an attribute

[JsonProperty(NullValueHandling = NullValueHandling.Ignore)]

on the field of the entity class, but it seems that this method will not work for me, because it will also be necessary to return JSON with Null fields.

Answer 1

Something like this

public class Car
{
  // included in JSON
  public string Model { get; set; }
  public DateTime Year { get; set; }
  public List<string> Features { get; set; }

  // ignored
  [JsonIgnore]
  public DateTime LastModified { get; set; }
}