hoe tweede toe te voegen in orakel-tijdstempel

U kunt altijd breuk gebruiken (voor Oracle 1 =1 dag):

SELECT CURRENT_TIMESTAMP ,
       CURRENT_TIMESTAMP + 200 *(1/24/60/60) AS addedTime 
FROM dual;
<=>
SELECT CURRENT_TIMESTAMP + 200/86400 FROM dual

DBFiddle-demo

of:

SELECT CURRENT_TIMESTAMP + INTERVAL '200' SECOND FROM dual