You should never believe me, but I have used spaces in my query between the function name and the parenthesis (and then mysql says: function does not exist, because that extra space ' ' after the function(!)).
But my query does not again not work.
) AS total
hour AS u
DATE_FORMAT(u.hour_begin, '%H:%i') != '00:00'
Now it says, that I should have a syntax error, at line 6.
If you have some knowledge, can someone check that line?
Edit: I try to use ADDTIME and ADDDATE and so on, but no result yielded.