In Oracle, the SYSTIMESTAMP function returns the current date and time with fractional seconds and with the time zone of the current database instance.
In PostgreSQL you can use the CURRENT_TIMESTAMP or NOW functions that also include fractional seconds and time zone.
Oracle:
-- Get the current datetime with time zone SELECT SYSTIMESTAMP FROM dual; /* 16-DEC-24 02.46.38.954000 PM +01:00 */
PostgreSQL:
-- Get the current datetime with time zone SELECT CURRENT_TIMESTAMP; /* 2024-12-16 14:46:38.954841+01 */
For more information, see Oracle to PostgreSQL Migration.