Contoh LINQ : Join Query

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

class Customer
{
public string ID { get; set; }
public string City { get; set; }
public string Country { get; set; }
public string Region { get; set; }
public decimal Sales { get; set; }
}
class Order
{
public string ID { get; set; }
public decimal Amount { get; set; }
}
class Program
{
static void Main(string[] args)
{
List orders = new List {
new Order { ID="X", Amount=900 },
new Order { ID="Y", Amount=1000 },
new Order { ID="Z", Amount=1100 }
};
List customers = new List {
new Customer { ID="X", City="Beijing", Country="China", Region="Asia", Sales=9000 },
new Customer { ID="Y", City="Bogotá", Country="Colombia", Region="South America", Sales=1001 },
new Customer { ID="Z", City="Lima", Country="Peru", Region="South America", Sales=2002 }
};

var queryResults =
from c in customers
join o in orders on c.ID equals o.ID
select new { c.ID, c.City, SalesBefore = c.Sales, NewOrder = o.Amount, SalesAfter = c.Sales+o.Amount };

foreach (var item in queryResults)
{
Console.WriteLine(item);
}
}
}