Something

mysql> set @t='2007-01-01 00:00:00';Query OK, 0 rows affected (0.00 sec)mysql> select date_format(timediff(now(),@t),'%Y-%m-%d %H:%i:%s');+-----------------------------------------------------+| date_format(timediff(now(),@t),'%Y-%m-%d %H:%i:%s') |+-----------------------------------------------------+| NULL                                                |+-----------------------------------------------------+1 row in set, 1 warning (0.00 sec)mysql> show warnings;+---------+------+---------------------------------------------------+| Level   | Code | Message                                           |+---------+------+---------------------------------------------------+| Warning | 1292 | Truncated incorrect datetime value: '10579:13:15' |+---------+------+---------------------------------------------------+1 row in set (0.00 sec)mysql> select time_format(timediff(now(),@t),'%Y-%m-%d %H:%i:%s');+-----------------------------------------------------+| time_format(timediff(now(),@t),'%Y-%m-%d %H:%i:%s') |+-----------------------------------------------------+| 0000-00-00 10579:19:00                              |+-----------------------------------------------------+1 row in set (0.00 sec)