How to insert a timestamp in Oracle?

Solution 1:

insert
into tablename (timestamp_value)
values (TO_TIMESTAMP(:ts_val, 'YYYY-MM-DD HH24:MI:SS'));

if you want the current time stamp to be inserted then:

insert
into tablename (timestamp_value)
values (CURRENT_TIMESTAMP);

Solution 2:

INSERT
INTO    mytable (timestamp_field)
VALUES  (CURRENT_TIMESTAMP)

CURRENT_TIMESTAMP and SYSTIMESTAMP are Oracle reserved words for this purpose. They are the timestamp analog of SYSDATE.