Thanks for all your answers, it is working now.
Christoph Haller <ch(at)rodos(dot)fzk(dot)de> writes:
> Are you sure the MAX function will work on your
> text resp. char/varchar attribute 'semester'?
Yes, this works, I think because the ASCII (or whatever) value of 's'
is lower than that of 'w'.
Greetings,
joachim