When I execute the example from http://dev.mysql.com/doc/refman/5.5/en/date-and-time-functions.html#function_subtime I don't get the answer in the format shown there. This is the example:
mysql> SELECT SUBTIME('2007-12-31 23:59:59.999999','1 1:1:1.000002');
-> '2007-12-30 22:58:58.999997'
But the answer I get is:
If you remove every second letter from that answer you get
...which is almost the expected string. Maybe the conversion from some internal format to the actual representation goes somehow wrong?
I used PhpMyAdmin to execute the SELECT on my provider's web server. With PhpMyAdmin on my local machine it works correctly, i.e. as shown in the MySQL docs.
EDIT: The answer I get is actually the string representation of the hexadecimal character values of the DATETIME string, see http://www.asciitable.com/. But I still don't know how that happens.