How can I determine installed SQL Server instances and their versions?
At a command line:
SQLCMD -L
or
OSQL -L
(Note: must be a capital L)
This will list all the sql servers installed on your network. There are configuration options you can set to prevent a SQL Server from showing in the list. To do this...
At command line:
svrnetcn
In the enabled protocols list, select 'TCP/IP', then click properties. There is a check box for 'Hide server'.
You could query this registry value to get the SQL version directly:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\90\Tools\ClientSetup\CurrentVersion
Alternatively you can query your instance name and then use sqlcmd with your instance name that you would like:
To see your instance name:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\Instance Names
Then execute this:
SELECT SERVERPROPERTY('productversion'), SERVERPROPERTY ('productlevel'), SERVERPROPERTY ('edition')
If you are using C++ you can use this code to get the registry information.