I am adding distinct order count measure to the cube. I have to place it in a separate measure group for better performance When I click on "new measure group" button, I am presented with a dialog box "select a table from the source view" . My Facts_sales table is not on the list. because the table is already used by other measure group "Facts_sales".
How could I create a new measure group for the distinct count measure?
Just create a new measure in the group referencing the fact table of interest. As long as you select Distinct Count as the aggregation function, the new measure will auto-magically be placed in its own separate measure group.
EDIT: http://msdn.microsoft.com/en-us/library/ms166573.aspx