You can add aggregations manually either by creating an entirely new aggregation design, or creating a new aggregation in an already created aggregation design.
To add a new aggregation to the already existing aggregation design, follow the given steps:
Click the New Aggregation button in the Advanced View under Aggregations.
In the A0 column check the box in front of the
[Order Date].[Month], the[Order Date].[Hierarchy Order Date Calculations], and the[Product].[Product Subcategory]attributes.Process and deploy the cube.
Start a SQL Server Profiler trace with the Get Data From Aggregation selected.
Run the following code:
--Code 8.3 select {[Order Date].[Hierarchy].[Calendar Year].&[2005],[Order Date].[Hierarchy].[Calendar Year].&[2006], [Order Date].[Hierarchy].[Calendar Year].&[2007],[Order Date].[Hierarchy].[Calendar Year].&[2008]} on rows, [Product].[Product Hierarchy].[Product Subcategory] on columns from [Adventure Works DW2012] where...