1second(date) - Returns the second of date
2date is a string in the format of 'yyyy-MM-dd HH:mm:ss' or 'HH:mm:ss'.
3Example:
4   > SELECT second('2009-07-30 12:58:59') FROM src LIMIT 1;
5  59
6  > SELECT second('12:58:59') FROM src LIMIT 1;
7  59
8