Hi,
I think, it has nothing to do with report-definition from pega end. Probably, you can write use Connect-SQl method in an activity to extract data from two tables in two different data bases.

It is possible by creating hetrogenious connectivity (between Oracle and MSSQL) , where you can query the other db using the dblinks created from Oracle .

Thanks,
Haritha.D 

Hi Suresh,

Adding to haritha suggestion, you can also map your external table to the Pega class using External Class mapping wizard explained here. Then you can use this classes to fetch the data from the databases.

Regards

Mahesh

Getting data from 2 different tables that belongs to 2 different databases is not possible in Pega, provided you are trying to access the data in a single Rd rule using joins. Is this what you are looking for?