Query regarding calculation view

Hi,

1.) I have couple of doubts. While creating calculation view I cant see the option of SUM and DISTINCT in aggregation.

2.) I cant understand the use of aggregation node in calculation view since we can do the same in semantics by giving measure .

Instead of aggregation I can use projection  and result will be the same.

Also I have seen in couple of threads that aggregation node will be basically used with RAW tables. Can someone give me example of raw table and

how it can be used in aggregation node in calci view.

Thanks and Regards

Sumeet