How to: Identify a SQL Server Express Instance
You can use the sqlcmd utility to determine which edition of SQL Server is used for a currently-running instance. Microsoft SQL Server 2005 Express Edition (SQL Server Express) instances display "Express Edition."
To identify the version of SQL Server
Connect to an instance of SQL Server by using the following sqlcmd command:
sqlcmd -S Server\Instance
Where Server is the name of the computer and Instance is the name of the instance you want to check. If you have used the default named instance during setup, specify the instance as "SQLExpress".
To identify the server name and instance name, type the following command:
select @@servername go
When connected, type the following two commands:
select @@version go
Alternatively, you can type the following two commands:
select serverproperty('edition') go
The sqlcmd tool displays the version information. If the last line of information includes "Express Edition," the instance to which you are connecting is running SQL Server Express.