First thing to do is create a variable that creates the SQL string 'SELECT ''
You now have that to debug with easier.
Add a Debug.Print mySQL
Now check it in the Immediate window
Then pass it to the OpenRecordset()

This makes it much easier to read and even copy out into Notepad and check instead of trying to read it on a popup.

You could even check it with the Balance Braces tool.

It's just what the error says: you have an extra parenthesis.  Len('CON') + 1) should be Len('CON') + 1.