fonte: https://dba.stackexchange.com/questions/96629/how-to-grant-insert-in-a-table-that-is-in-another-database-on-sql-server-2008-r2

https://social.msdn.microsoft.com/Forums/sqlserver/en-US/4c12914c-8364-48f4-ad35-db64fbeb0ff1/how-to-give-read-write-permissions-to-a-specific-table-in-a-database-of-sql-2008r2?forum=sqlgetstarted

Use [DatabaseA]
GO

ALTER DATABASE [DatabaseA]
SET DB_CHAINING ON
GO

Use [DatabaseB]
GO
ALTER DATABASE [DatabaseB]
SET DB_CHAINING ON
GO

EXEC sp_grantdbaccess 'UserB';
GO 

GRANT SELECT, UPDATE on [DatabaseB].[dbo].[TableA] TO [UserB]
GO