TIMESTAMP WITH TIMEZONE - data is stored with a record kept of the time zone to which it refers.
TIMESTAMP WITH LOCAL TIMEZONE - data is normalized to the DB time zone on saving. When retrieved, it is normalized to the time zone of the user process selecting it.
INTERVAL YEAR TO MONTH - contains year-month
INTERVAL '123-2' YEAR(3) TO MONTH --the 3 suffix specifies the no. of digits to be consideres for YEAR.
INTERVAL '5-3' YEAR TO MONTH + INTERVAL'20' MONTH = INTERVAL '6-11' YEAR TO MONTH
INTERVAL DAY TO SECOND - contains day-hour-min-sec
INTERVAL'20' DAY - INTERVAL'240' HOUR = INTERVAL'10-0' DAY TO SECOND
TIMESTAMP WITH LOCAL TIMEZONE - data is normalized to the DB time zone on saving. When retrieved, it is normalized to the time zone of the user process selecting it.
INTERVAL YEAR TO MONTH - contains year-month
INTERVAL '123-2' YEAR(3) TO MONTH --the 3 suffix specifies the no. of digits to be consideres for YEAR.
INTERVAL '5-3' YEAR TO MONTH + INTERVAL'20' MONTH = INTERVAL '6-11' YEAR TO MONTH
INTERVAL DAY TO SECOND - contains day-hour-min-sec
INTERVAL'20' DAY - INTERVAL'240' HOUR = INTERVAL'10-0' DAY TO SECOND