Union and Intersect Operations Using LINQ

Introduction

Today, in this article let's play around with the most useful operations "union" and "intersect" in LINQ.

Union Operation using LINQ

Question: What is "union" operation?

In simple terms "It combines the data from two or more tables and shows them as a single result set".

Step 1: The data in the database looks like this:

Step 2: Create a new "ASP.NET Web Application", as in:

new-WebForm-project-in-ASP.NET.jpg

Step 3: The complete code of WebForm1.aspx looks like this:

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="LINQUnionApp.WebForm1" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

.grid

{

margin-top: 50px;

}

</style>

</head>

<body>

<div>

<table>

<tr>

<asp:Label ID="Label1" runat="server" Text="Union Operation using LINQ" Font-Bold="true"

Font-Size="Large" Font-Names="Verdana" ForeColor="Maroon"></asp:Label>

</td>

</tr>

<tr>

<asp:Button ID="Button1" runat="server" Text="Select Data" Font-Names="Verdana" Width="213px"

BackColor="Orange" Font-Bold="True" OnClick="Button1_Click" />

</td>

</tr>

<tr>

<asp:GridView ID="GridView1" runat="server" CssClass="grid" BackColor="LightGoldenrodYellow"

BorderColor="Tan" BorderWidth="1px" CellPadding="2" ForeColor="Black" GridLines="None">

</asp:GridView>

</td>

</tr>

</table>

</div>

</center>

</form>

</body>

</html>

Step 4: The complete code of WebForm1.aspx.cs looks like this:

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

namespace LINQUnionApp

{

public partial class WebForm1 : System.Web.UI.Page

{

protected void Page_Load(object sender, EventArgs e)

{

}

protected void Button1_Click(object sender, EventArgs e)

{

var queryEmp = from r in objEntities.Employeeselect new

{

Location = r.Location

};

var queryDept = from p in objEntities.Department select new

{

Location = p.Location

};

GridView1.DataSource = queryEmp.Union(queryDept);

GridView1.DataBind();

}

#region Instance MembersCompanyEntities objEntities = new CompanyEntities();

#endregion

}

Step 5: The output of the application looks like this:

Step 6: The data retrieved output of the application looks like this:

Intersect Operation using LINQ

Question: What is an "intersect" operation?

In simple terms "It combines the data from two or more tables and shows the common matching records as a single result set".

Step 1: The data in the database looks like this:

Step 2: Create a new "ASP.NET Web Application", as in:

Step 3: The complete code of WebForm1.aspx looks like this:

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="LINQIntersectApp.WebForm1" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

.grid

{

margin-top: 50px;

}

</style>

</head>

<body>

<div>

<table>

<tr>

<asp:Label ID="Label1" runat="server" Text="Intersect Operation using LINQ" Font-Bold="true"

Font-Size="Large" Font-Names="Verdana" ForeColor="Maroon"></asp:Label>

</td>

</tr>

<tr>

<asp:Button ID="Button1" runat="server" Text="Select Data" Font-Names="Verdana" Width="213px"

BackColor="Orange" Font-Bold="True" OnClick="Button1_Click" />

</td>

</tr>

<tr>

<asp:GridView ID="GridView1" runat="server" CssClass="grid" BackColor="LightGoldenrodYellow"

BorderColor="Tan" BorderWidth="1px" CellPadding="2" ForeColor="Black" GridLines="None">

</asp:GridView>

</td>

</tr>

</table>

</div>

</center>

</form>

</body>

</html>

Step 4: The complete code of WebForm1.aspx.cs looks like this:

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

namespace LINQIntersectApp

{

public partial class WebForm1 : System.Web.UI.Page

{

protected void Page_Load(object sender, EventArgs e)

{

}

protected void Button1_Click(object sender, EventArgs e)

{

var queryEmp = from r in objEntities.Employee

select new

{

Location = r.Location

};

var queryDept = from p in objEntities.Department

select new

{

Location = p.Location

};

GridView1.DataSource = queryEmp.Intersect(queryDept);

GridView1.DataBind();

}

#region Instance MembersCompanyEntities objEntities = new CompanyEntities();

#endregion

}

Step 5: The output of the application looks like this:

Step 6: The data retrieved output of the application looks like this:

Union and Intersect Operations Using LINQ

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