using System;

using System.Linq;

using Microsoft.EntityFrameworkCore;

using Microsoft.EntityFrameworkCore.SqlServer;

public class Program

{

    public static void Main()

    {

        using var ctx = new MyContext();

        var baseQuery = ctx.Tests;

        var a = baseQuery.Where(t => t.Id < 10);

        var b = baseQuery.Where(t => t.Id < 20);

        var c = baseQuery.Where(t => t.Id < 30);

        var bExC = b.Except(c);

        var results = a.Except(b);

        Console.WriteLine(results.ToQueryString());

    }

}

​

public class MyContext : DbContext

{

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)

    {

        optionsBuilder.UseSqlServer("Data Source=.");

    }

    public DbSet<TestEntity> Tests {get;set;} = null!;

}

​

[Keyless]

public class TestEntity

{

    public int Id {get;set;}

    public string SomeData {get;set;}

}