Show dynamic days with Month Dates in a Oracle Apex Grid Heading - oracle-apex

Question

I want to update Interactive grid Column Heading Name dynamically in oracle apex on the basis of month selected from list.
For example I have selected August from Month LOV then the column heading should be display like this.
01/MON, 02/TUE, 03/WED .............. 28/SAT,29/SUN,30/MON.
Previous Research
Code: I try to CONCATENATE date like this.
---------------For First Column Heading-----------
SELECT '01'||' / '|| TO_CHAR(:P152_START_DATE,'DAY')
FROM DUAL;
---------------For First Column Heading-----------
SELECT '02'||' / '|| TO_CHAR(:P152_START_DATE+1,'DAY')
FROM DUAL;
This is the interactive grid having column heading from 01-Aug-2021 to 31-Aug-2021.

Answer 1

A column header supports substitutions, so this is one solution.
Create 31 page items P152_COL1 up to P152_COL31.
Set page item for each column heading using substitution syntax (example &P152_COL1. )
Create a page process to populate the column header page items
BEGIN
FOR r IN
(SELECT TO_CHAR(TRUNC(TO_DATE(:P152_START_DATE, 'DD-MON-YYYY'),'MM') + level - 1,'DD/DY') AS wd,
TO_DATE(:P152_START_DATE, 'DD-MON-YYYY') + level - 1 as dt,
level - 1 as rn
FROM dual CONNECT by level < 32)
LOOP
--only include the days of the selected month, else print "-"
IF TRUNC(r.dt,'MM') = TRUNC(TO_DATE(:P152_START_DATE, 'DD-MON-YYYY'),'MM') THEN
APEX_UTIL.SET_SESSION_STATE('P152_COL'||r.rn,r.wd);
ELSE
APEX_UTIL.SET_SESSION_STATE('P152_COL'||r.rn,'-');
END IF;
END LOOP;
END;
Note that I assumed date format DD-MON-YYYY for the P152_START_DATE page item - adjust as needed for your project