Someone could help in a way to query another DB in same server ?

In a normal way we made

SELECT dbo._Name, dbo._Adress FROM anotherdb.dbo.table WHERE something

but if i made it in the reports section it give a empty query.

That trick will work, but it is a very unsupported workaround that will affect your entire installation (all portals using the same codebase). However, the next version of Reports (coming in the next month or so, hope to have some more news soon, keep an eye on the DNN blogs) will allow a module to query, not only another database, but completely different data sources including other SQL Servers, OLE DB, and others.

Andrew Nurse
DotNetNuke Core Team Member and Reports Module Project Lead
Microsoft Certified Professional Developer

If you know the appropriate connection string to access the "other" database.  You can use a module like SQLGridSelectedView (www.tressleworks.ca) or SQLView (www.dnnstuff.com) to access the database.  These modules are free and allow the user  to specify the connection string to be used when accessing a database.  

For example, you can use the existing DNN database connection string where the database is defined and change it to the "other" database, then you can perform selects without referencing the database name.    If you have Northwind example database installed, you can used something like:

Server=(local);Database=Norhtwind;uid=uuuu;pwd=ppppp;

as the connection string.  For help with connection strings, see www.connectionstrings.com   Based on the connection string you can access a Excel file,  MS Access, Oracle, MySQL, and many other data stores.

Hope this helps,
Paul.