Aggregate, LINQ, c#

The following code finds a list of Quantity values ok.

Question: At line 2, how aggregate could be applied to this code to get total quantity?

            Dim s List(Of Order)= (From o In db.Orders Where o.ID = 2).ToList()

            Dim sum = From o In s.OrderItems Select Total = o.Quantity

Open in new window

LVL 34
Mike EghtebasDatabase and Application DeveloperAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

it_saigeDeveloperCommented:
Are you looking for something like this:
Imports System.Linq

Module Module1
	Private orders As New List(Of Order) From _
	 { _
	  New Order() With {.ID = 1, .Quantity = 5}, _
	  New Order() With {.ID = 2, .Quantity = 12}, _
	  New Order() With {.ID = 3, .Quantity = 7}, _
	  New Order() With {.ID = 2, .Quantity = 2}, _
	  New Order() With {.ID = 1, .Quantity = 1}, _
	  New Order() With {.ID = 3, .Quantity = 8} _
	 }

	Sub Main()
		Console.WriteLine(String.Format("Quantity of Orders for OrderID 2 = {0}", (Aggregate order As Order In orders Where order.ID.Equals(2) Into Sum(order.Quantity))))
		Console.ReadLine()
	End Sub
End Module

Class Order
	Property ID() As Integer
	Property Quantity() As Integer
End Class

Open in new window


Produces the following output:Capture.JPG
-saige-
0
Mike EghtebasDatabase and Application DeveloperAuthor Commented:
Hi Saige,

Orders is in Entity Framework define by db and has data in it.

Dim db As New TestDatabaseEntities


I want to pull that data. If I were doing it in SQL:

Select Sum(o.Quantity) From tblOrders  o Where o.ID =2

or

Select o,ID, Sum(o.Quantity) From tblOrders  Group By o.ID Having ID =2
0
Fernando SotoRetiredCommented:
Hi eghtebas;

Try these out, it should give you what you are looking for.

'' Select Sum(o.Quantity) From tblOrders  o Where o.ID =2
Dim sumQuty = (From o In db.tblOrders
               Where o.ID = 2
               Select o.Quantity).Sum()


'' Select o,ID, Sum(o.Quantity) From tblOrders  Group By o.ID Having ID =2               
Dim sumQuty2 = From o In db.tblOrders
               Group o By ID = o.ID Into orderGroup = Group
               Where ID = 2
               Select ID, sumQuty = orderGroup.Sum(Function(q) q.Quantity)

Open in new window

0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
it_saigeDeveloperCommented:
Well you should still be able to use Aggregate, try:
'  This is the list of orders.
Dim s List(Of Order)= (From o In db.Orders Where o.ID = 2).ToList()
'  So long as Quantity is a property of order, we can sum it.
Dim sum = (Aggregate o In s Into Sum(o.Quantity))

Open in new window


-saige-
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Visual Basic.NET

From novice to tech pro — start learning today.

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.