I've read post that there are plug-ins that has to be used to communicate with turnstile. Plug-ins do not work in Filemaker Go, but you can have a plug-in designed for FMS and then send a command run script on server to perform the plug-in command. You might try doing a Google search for Filemaker turnstile plug-ins.
The ExecuteSQL is going to retrieve data from the SQL server to be placed in a field in FM, so I don't see this working. You would need a live connecting to the SQL server. http://www.filemaker.com/support/technologies/odbc.html
I don't think there would be any difference in using a barcode or a finger print scanner to open and close the turnstile, because after testing for barcode or finger print then a command would be sent by the plug-in.