NULL.\n\nURL: https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html\n\n','mysql> SELECT ADDTIME(\'2007-12-31 23:59:59.999999\', \'1 1:1:1.000002\');\n        -> \'2008-01-02 01:01:01.000001\'\nmysql> SELECT ADDTIME(\'01:00:00.999999\', \'02:00:00.999998\');\n        -> \'03:00:01.999997\'\n','https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html');