So here is how to subtotal a column that is itself a sum function. SSRS 2005 wont allow you to aggregate an aggregate function. For example, the total of a column showing a Running Total, useful in daily stock balance calculations.
Add the following code to the report Report > Properties
Dim public totalBalance As Decimal
Public Function AddTotal(ByVal balance As Decimal) AS Decimal
totalBalance = totalBalance + balance
return balance
End Function
Public Function GetTotal()
return totalBalance
End Function
This code adds two variables: totalbalance and cnt as decimal numbers. And two functions AddTotal and GetTotal.
AddTotal allows items in rows to be added up, use as follows in a value cell, where you had;
=RunningTotal(Fields!ColumnName.Value,sum,nothing)
with
=Code.AddTotal(RunningTotal(Fields!ColumnName.Value,sum,nothing))
in the total cell, where it you were unable to simply use
=sum(RunningTotal(Fields!ColumnName.Value,sum,nothing))
use instead
=Code.GetTotal()
Simply add more variables and public functions if you need to sum the sum of more that one field.
Inspired by this post on averages of averages link