using System;

using System.Collections.Generic;

using System.Linq;

public class Program

    {

        /*

         * 

         * https://stackoverflow.com/questions/65190666/linq-to-entities-syntax-help-when-having-two-tables

         * 

         * */

​

        public static void Main(string[] args)

        {

            var vehicles = GetVehicles();

            var assignedToVehicle = GetAssignedToVehicle();

​

            var result = vehicles.Where(car => car.DeletedAt == null &&

                                        !assignedToVehicle.Any(assigned => assigned.VehicleId == car.Id))

                                    .AsQueryable();

​

            foreach (var car in result)

            {

                Console.WriteLine("Vehicle name: " + car.Name);

            }

        }

​

        public static List<Vehicle> GetVehicles()

        {

            return new List<Vehicle>() {

                new Vehicle(){ Id = 1, Name = "Audi", DeletedAt = DateTime.Now },

                new Vehicle(){ Id = 2, Name = "Mazda", DeletedAt = DateTime.Now.AddDays(-1)},

                new Vehicle(){ Id = 3, Name = "Suzuki", DeletedAt = null },

                new Vehicle(){ Id = 4, Name = "Ford", DeletedAt = DateTime.Now.AddDays(-2) },

                new Vehicle(){ Id = 5, Name = "Mercedes", DeletedAt = null },

                new Vehicle(){ Id = 6, Name = "Jaguar", DeletedAt = null }

            };

        }

​

        public static List<AssignedToVehicle> GetAssignedToVehicle()

        {

            return new List<AssignedToVehicle>() {

                new AssignedToVehicle(){ UserId = 100, VehicleId = 1, UnassignedAt = DateTime.Now },

                new AssignedToVehicle(){ UserId = 101, VehicleId = 2, UnassignedAt = DateTime.Now.AddDays(-3) },

                new AssignedToVehicle(){ UserId = 102, VehicleId = 3, UnassignedAt = DateTime.Now.AddDays(-4) },

                new AssignedToVehicle(){ UserId = 103, VehicleId = 4, UnassignedAt = DateTime.Now.AddDays(-5) }

            };

        }

​

    }

​

    public class Vehicle

    {

        public int Id { get; set; }

        public string Name { get; set; }

        public DateTime? DeletedAt { get; set; }

    }

​

    public class AssignedToVehicle

    {

        public int UserId { get; set; }

        public int VehicleId { get; set; }

        public DateTime? UnassignedAt { get; set; }

    }