SSRS running count across groups

The problem

You have a SSRS report which is grouping by a category.

Assume you have 6 items in two groups. You want the first column to be a running row count across the groups.

You Want a report that looks like this:

SSRS report with running total accross groups

The solution

In the “detail” cell for the first column use the following expression;

=RunningValue(1, Count, Nothing)