mysql select '1997-12-31 23:59:59' interval 1second; - '1998-01-01 00:00:00' mysql select interval 1 day '1997-12-31'; - '1998-01-01' mysql select '1998-01-01' - interval 1second; - '1997-12-31 23:59:59' mysql select date_add('1997-12-3123
mysql> select '1997-12-31 23:59:59' + interval 1second;   -> '1998-01-01 00:00:00'
mysql> select interval 1 day + '1997-12-31';
   -> '1998-01-01'
mysql> select '1998-01-01' - interval 1second;
   -> '1997-12-31 23:59:59'
mysql> select date_add('1997-12-3123:59:59',interval 1 second);
   -> '1998-01-01 00:00:00'
mysql> select date_add('1997-12-3123:59:59',interval 1 day);
   -> '1998-01-01 23:59:59'
mysql> select date_add('1997-12-3123:59:59',interval '1:1' minute_second);
   -> '1998-01-01 00:01:00'
mysql> select date_sub('1998-01-0100:00:00',interval '1 1:1:1' day_second);
   -> '1997-12-30 22:58:59'
mysql> select date_add('1998-01-0100:00:00',interval '-1 10' day_hour);
   -> '1997-12-30 14:00:00'
mysql> select date_sub('1998-01-02', interval 31day);
   -> '1997-12-02'
mysql> select date_add('1992-12-3123:59:59.000002',interval '1.999999' second_microsecond);
   -> '1993-01-01 00:00:01.000001'