SSRS Expression - Aggregating variables

Question

I'm building a report where I'm trying to write an expression for a variable (not parameter). I'm planning on creating multiple variables, each referencing the SUM(SUM()) of amounts from different datasets. I'm then planning on referencing each of these variables in a single textbox to do a calculation. This is to circumvent SSRS' limitation of using multiple datasets in a single tablix/matrix.

I need some assistance with the syntax. When I use SUM by itself, the report runs fine and I can perform calculations on these values without issues. For example, this works fine:

Variable1:

=SUM(Fields!Amount.Value, "DataSet1")

Variable2:

=SUM(Fields!Amount.Value, "DataSet2")

Textbox1:

=Variable1.Value - Variable2.Value

But I get an error when trying to amend it to the following (which is what I actually need):

Variable1:

=SUM(SUM(Fields!Amount.Value, "DataSet1"))

I get an error saying "The variable expression for the report 'body' uses an aggregate expression without a scope. A scope is required for all aggregates used outside of a data region unless the report contains exactly one dataset." I have a hunch that there's a problem with my syntax/parantheses placement. I tried adding ",DataSet1" again, at the end (SUM(SUM(Fields!Amount.Value, "DataSet1"),"DataSet1") but receive an error about recursive nesting problems. Any suggestions?

Answer 1

I'm guessing where you assign the variable, it doesn't have the concept of these column groups, so the only option is to sum the entire dataset.

I think you can try one of the following:

1. Assign the value from within the tablix (if it lets you, you might need custom code which aggregates and then sets the variable)
2. Specify the grouping condition again in a conditional sum, like SUM(IIF(Fields!Location.Value = TheLocationValueForTheColumnYouNeed, Fields!Amount.Value, 0))