LINQ和MYSQL不支持指定的方法

Question

I've tried to write a LINQ query that will give me all the details in one place, I need the date of production, the employee name and the sum of money this employee should get for his work. this is what I have so far:

var PrePerWorker =
                    (from Production in context.production
                    where Production.ProductionDate >= dtpStartDate.SelectedDate && Production.ProductionDate <= dtpEndDate.SelectedDate

                    select new
                    {
                        Worker = 
                            (from Employee in context.employees
                             where Employee.ID == Production.EmpID
                            select Employee.FirstName).FirstOrDefault(),
                        DateOfProduction = Production.ProductionDate,
                        Total =
                            Production.Side == 1 ? Production.Amount * 
                            (from Product in context.products
                             where Product.ProductID == Production.ProductID
                             select Product.SideA).FirstOrDefault():
                             Production.Side == 2 ? Production.Amount * 
                            (from Product in context.products
                             where Product.ProductID == Production.ProductID
                             select Product.SideB).FirstOrDefault():
                             Production.Side == 3 ? Production.Amount * 
                            (from Product in context.products
                             where Product.ProductID == Production.ProductID
                             select Product.SideC).FirstOrDefault(): 0
                    }).GroupBy(x => x.DateOfProduction, x => x.Worker);

When I run this and then try to iterate over the results I get an error saying "Specified method is not supported".
Anyone knows why? and how can I fix this?

Answer 1

My guess is that the tertiary ? : operator can't be translated to SQL

Answer 2

For grouping by 2 columns you need GroupBy(x => new {x.DateOfProduction, x.Worker}); . And can you explain what you need, because your linq looks like so hard for me.