C#: Generate a Left Join between two data sets

C# Sharp LINQ : Exercise-26 with Solution

Write a program in C# Sharp to generate a Left Join between two data sets.

Sample Solution:

C# Sharp Code:

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

class  LinqExercise26
{
    static void Main(string[] args)
    {
        // Creating a list of Item_mast objects
        List<Item_mast> itemlist = new List<Item_mast>
        {  
            // Initializing Item_mast objects with ItemId and ItemDes properties
            new Item_mast { ItemId = 1, ItemDes = "Biscuit  " }, 
            new Item_mast { ItemId = 2, ItemDes = "Chocolate" }, 
            new Item_mast { ItemId = 3, ItemDes = "Butter   " },  
            new Item_mast { ItemId = 4, ItemDes = "Brade    " },  
            new Item_mast { ItemId = 5, ItemDes = "Honey    " }  
        }; 

        // Creating a list of Purchase objects
        List<Purchase> purchlist = new List<Purchase>
        {  
            // Initializing Purchase objects with InvNo, ItemId, and PurQty properties
            new Purchase { InvNo=100, ItemId = 3,  PurQty = 800 }, 
            new Purchase { InvNo=101, ItemId = 2,  PurQty = 650 }, 
            new Purchase { InvNo=102, ItemId = 3,  PurQty = 900 },  
            new Purchase { InvNo=103, ItemId = 4,  PurQty = 700 },
            new Purchase { InvNo=104, ItemId = 3,  PurQty = 900 },  
            new Purchase { InvNo=105, ItemId = 4,  PurQty = 650 },  		
            new Purchase { InvNo=106, ItemId = 1,  PurQty = 458 }  
        }; 

        // Displaying the contents of the Item_mast list
        Console.Write("\nLINQ : Generate a Left Join between two data sets : "); 
        Console.Write("\n--------------------------------------------------\n");
        Console.Write("Here is the Item_mast List : ");
        Console.Write("\n-------------------------\n");

        foreach (var item in itemlist)
        {
            // Displaying ItemId and ItemDes of each Item_mast object
            Console.WriteLine(
                "Item Id: {0}, Description: {1}",
                item.ItemId,
                item.ItemDes);
        }

        // Displaying the contents of the Purchase list
        Console.Write("\nHere is the Purchase List : ");
        Console.Write("\n--------------------------\n");

        foreach (var item in purchlist)
        {
            // Displaying InvNo, ItemId, and PurQty of each Purchase object
            Console.WriteLine(
                "Invoice No: {0}, Item Id : {1},  Quantity : {2}",
                item.InvNo,
                item.ItemId,
                item.PurQty);
        }

        Console.Write("\nHere is the list after joining  : \n\n");

        // Performing a left outer join between itemlist and purchlist using LINQ
        var leftOuterJoin = from itm in itemlist
                            join prch in purchlist
                            on itm.ItemId equals prch.ItemId
                            into a
                            from b in a.DefaultIfEmpty(new Purchase())
                            select new
                            {
                                itid = itm.ItemId,
                                itdes = itm.ItemDes,
                                prqty = b.PurQty
                            };

        // Displaying the results of the left outer join
        Console.WriteLine("Item ID\t\tItem Name\tPurchase Quantity");
        Console.WriteLine("-------------------------------------------------------");
        foreach (var data in leftOuterJoin)  
        {  
            // Displaying ItemId, ItemDes, and PurQty after the left outer join operation
            Console.WriteLine(data.itid + "\t\t" + data.itdes + "\t\t" + data.prqty);  
        }           
        Console.ReadLine();
    }
}

// Class representing the Item_mast object
public class Item_mast
{
    public int ItemId { get; set; } // Property for Item ID
    public string ItemDes { get; set; } // Property for Item Description
}

// Class representing the Purchase object
public class Purchase
{
    public int InvNo { get; set; } // Property for Invoice Number
    public int ItemId { get; set; } // Property for Item ID
    public int PurQty { get; set; } // Property for Purchase Quantity
}

Sample Output:

LINQ : Generate a Left Join between two data sets :                                                           
--------------------------------------------------                                                            
Here is the Item_mast List :                                                                                  
-------------------------                                                                                     
Item Id: 1, Description: Biscuit                                                                              
Item Id: 2, Description: Chocolate                                                                            
Item Id: 3, Description: Butter                                                                               
Item Id: 4, Description: Brade                                                                                
Item Id: 5, Description: Honey                                                                                 
Here is the Purchase List :                                                                                   
--------------------------                                                                                    
Invoice No: 100, Item Id : 3,  Quantity : 800                                                                 
Invoice No: 101, Item Id : 2,  Quantity : 650                                                                 
Invoice No: 102, Item Id : 3,  Quantity : 900                                                                 
Invoice No: 103, Item Id : 4,  Quantity : 700                                                                 
Invoice No: 104, Item Id : 3,  Quantity : 900                                                                 
Invoice No: 105, Item Id : 4,  Quantity : 650                                                                 
Invoice No: 106, Item Id : 1,  Quantity : 458 
Here is the list after joining  :                                                                             
                                                                                                       
Item ID         Item Name       Purchase Quantity                                                             
-------------------------------------------------------                                                       
1               Biscuit                 458                                                                   
2               Chocolate               650                                                                   
3               Butter                  800                                                                   
3               Butter                  900                                                                   
3               Butter                  900                                                                   
4               Brade                   700                                                                   
4               Brade                   650                                                                   
5               Honey                   0

Flowchart:

C# Sharp Code Editor:

Contribute your code and comments through Disqus.

Previous: Write a program in C# Sharp to generate an Inner Join between two data sets.
Next: Write a program in C# Sharp to generate a Right Outer Join between two data sets.