compare fields from two datasets

Hello,
How can I solve this problem.
For example, I have two databases. db1 and db2.
I want to compare two float fields from tables from db1 and db2 and the present the difference between these fields in a column in reporting services.

ex. loop1
value from db1.table_db1
4

value from db2.table_db2
6

diff
2

ex. loop2
value from db1.table_db1
2

value from db2.table_db2
2

diff
0

..continues...

Should I create 2 datasets and 2 datasources? Must I write custom code for this?

Regards

Are the two databases on the same server or on the different servers?

If they are on the different servers then use the SQL Server linked servers feature.

|||nope they are on the same server