my suggestion...

1. none sas -- it seemed to me that you are using oracle pl/sql. if that's the case, try using materialized view or indexed view with ms sql server;
2. it seemed to me that you are querying data directly from oltp rather than olap, if that's the case, you may be better to have olap, or at least using staging db to reduce the volumn of data (i.e. from b to m)
3. re-consider your db architecture design

your feedback is appreciated.