LINQ Inner Join

In LINQ, Inner join is used to return only the matched records or elements from the collections based on the specified conditions.

Syntax of LINQ Inner Join

Here is the syntax of using the LINQ Inner join to get the elements from the collections based on the specified condition.

var result = from d in objDept
join e in objEmp
on d.DepId equals e.DeptId
select new
{
EmployeeName = e.Name,
DepartmentName = d.DepName
};

From the above syntax, we are trying to get the elements from "objEmp", "objDept" collections based on the matching "DeptId" column values.

Example of LINQ Inner Join

Here is the example of using the LINQ Inner join to get the elements from the collection based on the specified conditions.

C# Code

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

namespace ConsoleApp1
{
    class Programme2
    {
        static void Main(string[] args)
        {
   /* create an object of the class 'department' and create a 
    list of the department with the added record*/
            List<Department> Dept = new List<Department>
    (){
    new Department{DepId=1,DepName="Software"},
    new Department{DepId=2,DepName="Finance"},
    new Department{DepId=3,DepName="Health"}
    };
    /* create an object of the class 'Employee' and create a
    list of the Employee with the added record*/
    List<Employee>Emp = new List<Employee>
    ()
    {
    new Employee { EmpId=1,Name = "Akshay Tyagi", DeptId=1 },
    new Employee { EmpId=2,Name = "Vaishali Tyagi", DeptId=1 },
    new Employee { EmpId=3,Name = "Arpita Rai", DeptId=2 },
    new Employee { EmpId=4,Name = "Sateesh Alavala", DeptId =2},
    new Employee { EmpId=5,Name = "Madhav Sai"}
    };
    /*Linq query apply to fetch the information of the
    employee name and department name
    here we mapped the employee with the department and store the result in the variable 'result'*/
    var result = from d in Dept
    join e in Emp
    on d.DepId equals e.DeptId
    select new
    {
    EmployeeName = e.Name,
    DepartmentName = d.DepName
    };
    //foreach loop traverse all the data in the result variable and store in item variable
    foreach (var item in result)
    {
   /* Console.WriteLine(item.EmployeeName + "\t | " + item.DepartmentName)
    will print the name of the employee and name of the department*/
    Console.WriteLine(item.EmployeeName + "\t | " + item.DepartmentName);
    }
    Console.ReadLine();
    }
    }
    //Create class 'Department' and 'Employee' and set the variable name
    class Department
    {
    public int DepId { get; set; }
    public string DepName { get; set; }
    }
    class Employee
    {
    public int EmpId { get; set; }
    public string Name { get; set; }
    public int DeptId { get; set; }
    }
    }

Output: