hvordan man tilføjer anden i oracle tidsstempel

Du kan altid bruge brøk (for 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

eller:

SELECT CURRENT_TIMESTAMP + INTERVAL '200' SECOND FROM dual