using System;

using System.Linq;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

    }

    public class Test

    {

        public void Method1()

        {

            var tables = Enumerable.Empty<Table>();

​

            int orderInput = 13000;

            string customerInput = "";

            int employeeInput = 20;

​

            var q = tables

                .Where(t => t.OrderId == 0 || t.OrderId < orderInput)

                .Where(t => string.IsNullOrWhiteSpace(t.CustomerId) || t.CustomerId == customerInput)

                .Where(t => t.OrderId == 0 || t.OrderId < employeeInput);

        }

        public void Method2()

        {

            var tables = Enumerable.Empty<Table>();

​

            var aInputModel = new InputModel()

            {

                orderInput = 13000,

                customerInput = "",

                employeeInput = 20,

            };

​

            var q = tables.Where(t => aInputModel.IsMatch(t));

        }

​

        public class Table

        {

            public int OrderId { get; set; }

            public string CustomerId { get; set; }

            public int EmployeeId { get; set; }

​

​

        }

        public class InputModel

        {

            public int orderInput { get; set; }

            public string customerInput { get; set; }

            public int employeeInput { get; set; }

​

            private bool IsOrderIdMatch(int orderId) => orderInput == 0 || orderId < orderInput;

            private bool IsCustomerIdMatch(string customerId) => string.IsNullOrWhiteSpace(customerInput) || customerId == customerInput;

            private bool IsEmployeeMatch(int employeeId) => employeeInput == 0 || employeeId < employeeInput;

​

            public bool IsMatch(Table aTable) => IsOrderIdMatch(aTable.OrderId)

                && IsCustomerIdMatch(aTable.CustomerId)

                && IsEmployeeMatch(aTable.EmployeeId);

        }

​

    }

}