I'm afraid it did not work. I got an error. I have searched the internet and found similar problems. But the answer is too complicated for me to understand. And I do not even know if it is relevant anymore (with the current mysql and php version).
Do you think this can help in any way, otherwise I have to put this down - and think of another solution.
https://stackoverflow.com/questions/2043259/how-to-join-to-first-row