Add Day, Hour, Minute, Second to a Date Value in Oracle

1. Add a day.
   select to_date('02-22-2008 10:30:30','mm-dd-yyyy hh24:mi:ss') today,
   to_date('02-22-2008 10:30:30','mm-dd-yyyy hh24:mi:ss')+1 next_day
   from dual;
   TODAY NEXT_DAY
   ------------------------- -------------------------
   02-22-08 10:30:30 -> 02-23-08 10:30:30
2. Add an hour.select to_date('02-22-08 10:30:30','mm-dd-yy hh24:mi:ss') today,
   to_date('02-22-08 10:30:30','mm-dd-yy hh24:mi:ss')+ 1/24 next_hour
   from dual;
   TODAY NEXT_HOUR
   ------------------------ ------------------------
   02-22-08 10:30:30 -> 02-22-08 11:30:30
3. Add a minute.
   select to_date('02-22-08 10:30:30','mm-dd-yy hh24:mi:ss') today,
   to_date('02-22-08 10:30:30','mm-dd-yy hh24:mi:ss')+ 1/(24*60) next_min
   from dual;
   TODAY NEXT_MIN
   ------------------------ ------------------------
   02-22-08 10:30:30 -> 02-22-08 10:31:30
4. Add a second.
   select to_date('02-22-08 10:30:30','mm-dd-yy hh24:mi:ss') today,
   to_date('02-22-08 10:30:30','mm-dd-yy hh24:mi:ss')+ 1/(24*60*60) next_sec
   from dual;
   TODAY NEXT_SEC
   ------------------------ ------------------------
   02-22-08 10:30:30 02-22-08 10:30:31
5. Subtract a day.
   select to_date('02-22-2008 10:30:30','mm-dd-yyyy hh24:mi:ss') today,
   to_date('02-22-2008 10:30:30','mm-dd-yyyy hh24:mi:ss') - 1 prev_day
   from dual;
   TODAY PREV_DAY
   ------------------------- -------------------------
   02-22-08 10:30:30 -> 02-21-08 10:30:30
6. Subtract an hour.
   select to_date('02-22-08 10:30:30','mm-dd-yy hh24:mi:ss') today,
   to_date('02-22-08 10:30:30','mm-dd-yy hh24:mi:ss') - 1/24 prev_hour
   from dual;
   TODAY PREV_HOUR
   ------------------------ ------------------------
   02-22-08 10:30:30 -> 02-22-08 09:30:30
7. Subtract a minute.
   select to_date('02-22-08 10:30:30','mm-dd-yy hh24:mi:ss') today,
   to_date('02-22-08 10:30:30','mm-dd-yy hh24:mi:ss') - 1/(24*60) prev_min
   from dual;
   TODAY PREV_MIN
   ------------------------ ------------------------
   02-22-08 10:30:30 -> 02-22-08 10:29:30
8. Subtract a second.
   select to_date('02-22-08 10:30:30','mm-dd-yy hh24:mi:ss') today,
   to_date('02-22-08 10:30:30','mm-dd-yy hh24:mi:ss') - 1/(24*60*60) prev_sec
   from dual;
   TODAY PREV_SEC
   ------------------------ ------------------------
   02-22-08 10:30:30 -> 02-22-08 10:30:29