How to optimize a query that compares data from the same day for each month - oracle

Question

I have a query that gets data from a given day and compares it with the same business day for each month (if it turns to be Sat, Sun, or holiday it should show the last day before i.e. if I say 25, it will return Sep 23, 2022, for September and Aug 25 for August, etc). DAILY_DATA table contains business days only, so this works:
SELECT *
FROM DAILY_DATA A, --It has partitions for every day, like 'PART_300922'
( SELECT TO_CHAR(DATE,'MM'),MAX(DATE) DATE
FROM DAILY_DATA
WHERE TO_CHAR(DATE,'YYYY')='2022'
AND TO_CHAR(DATE,'DD')<=TO_CHAR(TO_DATE(&query_date),'DD')
GROUP BY TO_CHAR(DATE,'MM')
)B
WHERE A.DATE = B.DATE
ORDER BY 1;
The problem is, it takes so long time cause it loops thorough the entire table, is there a way to optimize it? maybe using partitions or something?
Help please.

Answer 1

Try this:
WITH prep_daily_data(dat, dim, mdat) AS (
SELECT
d.dat,
TO_CHAR( d.dat , 'DD'),
TO_NUMBER(TO_CHAR(d.dat,'YYYYMM')) as mdat
FROM daily_data d
),
matching_dim(dat, next_dat) AS (
SELECT cm.dat, nm.dat
FROM prep_daily_data cm
JOIN prep_daily_data nm ON cm.dim = nm.dim AND cm.mdat+1 = nm.mdat
),
matching_others(dat, next_dat) AS (
SELECT dat, MAX(next_dat) FROM (
SELECT cm.dat AS dat, nm.dat AS next_dat
FROM prep_daily_data cm
JOIN prep_daily_data nm ON cm.dim > nm.dim AND cm.mdat+1 = nm.mdat
WHERE NOT EXISTS(SELECT 1 FROM matching_dim d WHERE d.dat = cm.dat)
)
GROUP BY dat
)
SELECT * FROM (
SELECT * FROM matching_dim
UNION ALL
SELECT * FROM matching_others
)
ORDER BY dat
;