SQL Server distributed databases

Question

how to link two different database in same SQL Server instance and send queries between them

Answer 1

use like below.

DB1.dbo.TableFromDB1
DB2.dbo.TableFromDB2

DB - database

Answer 2

Look at using synonyms "CREATE SYNONYM".

You can access the databases directly with a full path. But, that code will break if the database is ever renamed or changed.

Using a synonym, the code can remain unchanged; when the database moves, just update the synonym.

This can be useful when you have a test and production environment. The code does not have to change just because you move it from test to production and the database names do not have to be identical.