SAC - Show running number in table

Hello,

I am working with analytic application and I want to show a running number in my table.

I am working on a project planning application. Every project contains of several Items.

The user can add these items.

Example table 1:

Project 1

1 - Item A

2 - Item B

3 - Item C

table 2 with different project:

Project 2

1 - Item C

2 - Item A

I need to create this running number dynamically, based when the item was added (Date).

I already tried the "Count Dimension" Aggregation calculation measure (with project and also with item dimension as aggregation dimension) but this returns

Project 1

1 - Item A

1 - Item B

1 - Item C

and so on ...

Thanks!

Best regards

Michael