How to group by multiple columns with joins using linq - linq

Question

How to group by multiple columns coming from different tables and finally sum the amount column
var result = _employeeDAL.GetList(db =>
from es in db.Set<EmployeeSchedule>()
join est in db.Set<EmployeeSalaryType>() on est.Employee_Id equals es.Employee_Id
join et in db.Set<EmployeeType>() on est.Employee_Salary_Id equals et.Employee_Salary_Id
where es.Status == "JOINED" && es.JoinedDate.Year == 2017
select new
{
EmployeeName = es.EmployeeName
,Amount = est.Amount ///----------> SUM THIS
,EmployeeType = et.EmployeeType
});
Here's WHat I have tried
var result = _employeeDAL.GetList(db =>
from es in db.Set<EmployeeSchedule>()
join est in db.Set<EmployeeSalaryType>() on est.Employee_Id equals es.Employee_Id
join et in db.Set<EmployeeType>() on est.Employee_Salary_Id equals et.Employee_Salary_Id
group new { es, est, et } by new { es.EmployeeName, et.EmployeeType } into grp
where es.Status == "JOINED" && es.JoinedDate.Year == 2017
select new
{
EmployeeName = es.EmployeeName
,Amount = grp.Sum(g=>g.est.Amount)
,EmployeeType = et.EmployeeType
});

Answer 1

You are almost there. Just need to take into account that after the group ... by ... into grp clause the only variable in scope is grp.
So move the where clause before the group by and use grp.Key inside the select:
var result = _employeeDAL.GetList(db =>
from es in db.Set<EmployeeSchedule>()
join est in db.Set<EmployeeSalaryType>() on est.Employee_Id equals es.Employee_Id
join et in db.Set<EmployeeType>() on est.Employee_Salary_Id equals et.Employee_Salary_Id
where es.Status == "JOINED" && es.JoinedDate.Year == 2017
group new { es, est, et } by new { es.EmployeeName, et.EmployeeType } into grp
select new
{
EmployeeName = grp.Key.EmployeeName,
Amount = grp.Sum(g => g.est.Amount),
EmployeeType = grp.Key.EmployeeType,
});