How to dynamically add interval to timestamp? - oracle

Question

I need at some point to increment dynamically a timestamp plsql variable.
So, instead of doing this:
timestamp_ := timestamp_ + INTERVAL '1' DAY;
I would like to do thomething like this:
timestamp_ := timestamp_ + INTERVAL days_ DAY;
It doesn't really work.
My final goal is to dynamically create some scheduler jobs for some entities that have an variable expiration date, to avoid creating a single one which would be often executed.

Answer 1

It sounds like you want
timestamp_ := timestamp + numtodsinterval( days_, 'day' );
I would be somewhat cautious, however, about an architecture that involves creating thousands of scheduler jobs rather than one job that runs periodically to clear out expired rows. A single job is a heck of a lot easier to manage and oversee.

Answer 2

Special note:
1. INTERVAL YEAR TO MONTH and
2. INTERVAL DAY TO SECOND
are the only two valid interval datatypes;
Sample Example:
=============================
DECLARE
l_time INTERVAL YEAR TO MONTH;
l_newtime TIMESTAMP;
l_year PLS_INTEGER := 5;
l_month PLS_INTEGER := 11;
BEGIN
-- Notes :
-- 1. format is using "-" to connect year and month
-- 2. No need to mention any other keyword ; Implicit conversion takes place to set interval
l_time := l_year || '-' || l_month;
DBMS_OUTPUT.put_line ( l_time );
SELECT SYSTIMESTAMP + l_time INTO l_newtime FROM DUAL;
DBMS_OUTPUT.put_line ( 'System Timestamp :' || SYSTIMESTAMP );
DBMS_OUTPUT.put_line ( 'New Timestamp After Addition :' || l_newtime );
END;
=============================

Answer 3

Try this:
DECLARE
l_val NUMBER;
l_result VARCHAR2( 20 );
BEGIN
l_val := 1;
SELECT SYSDATE - INTERVAL '1' DAY * l_val INTO l_result FROM DUAL;
DBMS_OUTPUT.put_line( 'Current Date is ' || SYSDATE || ' minus ' || l_val || ' day(s) is ' || l_result );
END;
Output will be:
Current Date is 25-FEB-16 minus 1 day(s) is 24-FEB-16