The SYSDATE function returns the current date and time. It does
    not require any arguments.

    SYSDATE is a synonym for CURRENT_TIMESTAMP. As with CURRENT_
    TIMESTAMP, the return result of SYSDATE is affected by the
    setting of the SET DEFAULT DATE FORMAT statement, as shown in
    the following example:

    SQL> SET DEFAULT DATE FORMAT 'SQL99'
    SQL> SELECT SYSDATE, CURRENT_TIMESTAMP
    cont>  FROM RDB$DATABASE;

     1995-08-21 15:21:05.29   1995-08-21 15:21:05.29
    1 row selected
    SQL> SET DEFAULT DATE FORMAT 'VMS'
    SQL> SELECT SYSDATE, CURRENT_TIMESTAMP
    cont>  FROM RDB$DATABASE;

     21-AUG-1995 15:21:24.83   21-AUG-1995 15:21:24.83
    1 row selected