Linq query with nullable sum

Question

from i in Db.Items
select new VotedItem
{
    ItemId = i.ItemId,
    Points = (from v in Db.Votes
              where b.ItemId == v.ItemId
              select v.Poi         


        

Answer 1

I had a similar issue and came up with the solution of getting whatever I was trying to get out of the database, do a count on those and then only if I had anything returned do a sum. Wasn't able to get the cast working for some reason so posting this if anyone else had similar issues.

e.g.

Votes = (from v in Db.Votes
          where b.ItemId = v.ItemId
          select v)

And then check to see if you've got any results so that you don't get null returned.

If (Votes.Count > 0) Then
    Points = Votes.Sum(Function(v) v.Points)
End If