Calculate percentage of total columns based on total column in SSRS Matrix

Question

Looking to add a column in my SSRS Matrix which will give me the percentage from the total column in that row.

I'm using the following expression, but keep getting 100% for my percentages (I'm assuming this is because the total is evaluated last, so it's just doing Total/Total?

=FORMAT((Fields!ID.Value/SUM(Fields!ID.Value)), "P")

The field ID is calcuted within SQL, not SSRS.

For example

Site   |  Value 1  |    %1   |   Value2  |   %2    |   Total
  1    |    20     |   50%   |    20     |   50%   |    40

Answer 1

Probably this is happening because you need define the right scope for the SUM function:

SUM(Fields!ID.Value,"group_name") instead of plain SUM(Fields!ID.Value)

Updated:

I needed some time to make an example since I didn't have reporting services available the first time I answered you.

You can see the result and the field values

Answer 2

Hard to provide details without more info on the setup of your groups, but you should look at using the scope option to the aggregate operators like SUM or first:

=SUM(Fields!ID.Value, "NameOfRowGrouping") / SUM(Fields!ID.Value, "TopLevelGroupName")

Also, to keep things clean, you should move your format out of the expression and to either the placeholder properties or textbox properties that contains your value.