Join databases

Select column_name from 
OpenRowset(
        'SQLOLEDB',
        'Server=ServerName;UID=User;PWD=password;Database=databasetouse',
    'Exec stored_procedure_or_select'
         )


SELECT another_column
    FROM      OPENDATASOURCE(
             'SQLOLEDB',
             'Data Source=ServerName;User ID=User;Password=password'
             ).table_name