Question

What I have right now is this:

Dim users = From users In tempTable _
            Distinct Select users.Item("s_userid")
Dim usersCount As Integer = users.Count

But I pretty sure I shouldn’t have to do that. I should be able to get the count in/from that first linq query. What am I missing?

Answer 1

Dim distinctUserCount = (From users In tempTable
                    Let UserID = CInt(users.Item("s_userid"))
                    Select UserID).Distinct.Count

Another method would be to group the DataRows by your UserID-Column:

distinctUserCount  = (From users In tempTable
                    Let UserID = CInt(users("s_userid"))
                    Group users By UserID Into Group).Count

The “native” ADO.NET approach:

Dim view = new DataView(tempTable)
Dim TblDistinctUsers = view.ToTable(true, "s_userid")
distinctUserCount = TblDistinctUsers.Rows.Count

http://msdn.microsoft.com/en-us/library/wec2b2e6%28v=vs.100%29.aspx