Perform Self-Join using Lambda Operator

Introduction

In this blog we will see how to perform self-join using lambda operator.

Step 1: Create asp.net web application

SQL Script

Webform1.aspx

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="Self_Join_Using_Lambda.WebForm1" %>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:GridView ID="GridView1" runat="server"></asp:GridView>
</div>
</form>
</body>
</html>

Webform1.aspx.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace Self_Join_Using_Lambda
{
public partial class WebForm1 : System.Web.UI.Page
{
EmployeeDBEntities objEntities = new EmployeeDBEntities();
protected void Page_Load(object sender, EventArgs e)
{
//Self Join Using Lambda
var query = objEntities.Employees.Join(objEntities.Employees, p => p.ManagerId, q => q.EmpId, (p, q) => new { p.FirstName, q.ManagerName });
GridView1.DataSource = query.ToList();
GridView1.DataBind();
}
}
}