The database 'TestExpDb' cannot be opened because it is version 661. This server supp orts version 655 and earlier. A downgrade path is not supported and Auto GO command in batch while using SQLCMD.

Let me explain my query in detail: 1. I have installed MS SQL Server 2008 R2 on my machine version: Microsoft SQL Server 2008 R2 (SP1) - 10.50.2500.0 (X64)   Jun 17 2011 00:54:03   Copyright (c) Microsoft Corporation  Standard Edition (64-bit) on Windows NT 6.1 <X64>  (Build 7601: Service Pack 1)  2.On top of it I have added feature to add SQL Server express 2008 version: Microsoft SQL Server 2008 R2 (RTM) - 10.50.1600.1 (X64)   Apr  2 2010 15:48:46   Copyright (c) Microsoft Corporation  Express Edition with Advanced Services (64-bit)  on Windows NT 6.2 <X64> (Build 9200: )  3. Upon installing SQL express, I was able to create database (TestExpDb) through SQL server management studio.
4. After this, I detached database through SSMS. 5. Then tried attaching same through SSMS and I was able to do so. 6. Also when tried ...