Anyone know the generic practices transfer the database to SQL Server 2008 from SQL Server 2008 Express (I'm not sure it is r2), when I try to attach the .mdf file from Express, there is an error message.
the database cannot be opened because it is version 661. This server supports version 655 and earlier. A downgrade path is not supported.
Well, the message is clear: the file you're trying to attach from Express is from a newer version of SQL Server
So it appears that you indeed have SQL Server 2008 R2 Express, and you cannot attach this to a SQL Server 2008 instance. There's no way, no hack, no workaround, no trick, or no third-party tool to achieve this - it just cannot be done - period.
So you either need to upgrade your main instance to SQL Server 2008 R2, too - or you need to find another way (like scripting out the structure and/or data into .SQL files) to move your changes from one instance to the other - or use a third-party tool like Red-Gate SQL Compare to synchronize the changes between the two instances.
