Let Keyword In LINQ C#

Let =>The Let keyword allows storing the results of a query which can be used in a subsequent query; i.e., it creates a new variable and initializes it with the result of the expression you supply.

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace Test

{

    class Employee

    {

        public string Name { get; set; }

        public string EmpID { get; set; }

        public int Salary { get; set; }

    }

    class Program

    {

        static void Main(string[] args)

        {

            //Object Initialization for Employee class

            List<Employee> objEmployee = new List<Employee>{

                    new Employee{ Name="Sachin",EmpID="I001",Salary=800},

                    new Employee{ Name="Ankit",EmpID="I002",Salary=400},

                    new Employee{ Name="Vishal",EmpID="I003",Salary=250},

                    new Employee{ Name="Amit",EmpID="I004",Salary=300},

                    new Employee{ Name="Ravish",EmpID="I005",Salary=700},

                };          

            var objresult = from emp in objEmployee

                            let totalSalary = objEmployee.Sum(sal => sal.Salary)

                            let avgSalary = totalSalary / 5

                            where avgSalary > emp.Salary

                            select emp;

            foreach (var emp in objresult)

            {

                Console.WriteLine("Student: {0} {1}", emp.Name, emp.EmpID);

            }

            Console.ReadLine();

        }

    }

}

LINQ Query 
 

var result = from emp in objEmployee

                            let totalSalary = objEmployee.Sum(sal =>  sal.Salary)

                            let avgSalary = totalSalary / 5

                            where avgSalary > emp.Salary

                            select emp;

//output :

Student : Ankit 1002

Student : Vishal 1003

Student : Amit 1004

• Let – Doesn’t hide the previous variable and creates a new variable. Which means you create a new variable and you can also use the previous variable, so you can use both in further operations.