Select Max date column in a sql query, which is joined to other columns - sql

Question

I have an Oracle Query below
select papf.person_number, to_char(hrcd.SUBMITTED_DATE, 'DD-Mon-YYYY','NLS_DATE_LANGUAGE = American') as "Resignation Date", paam.last_update_date as assignmentupdate, hrcd.last_update_date as hrcdupdate, hth.last_update_date as hthupdate
from
per_all_people_f papf, per_all_assignments_m paam, hrc_txn_header hth, HRC_TXN_DATA hrcd
where
papf.person_id=paam.person_id
and paam.assignment_type IN ('E','C')
and paam.assignment_status_type in ('ACTIVE')
and paam.primary_flag = 'Y'
and paam.EFFECTIVE_LATEST_CHANGE ='Y'
and trunc(sysdate) between trunc(paam.effective_start_date) and trunc(paam.effective_end_date)
and trunc(sysdate) between trunc(papf.effective_start_date) and trunc(papf.effective_end_date)
and paam.person_id=hth.subject_id(+)
and paam.assignment_id=hth.object_id(+)
and hth.module_identifier(+) IN ('Resignation','Terminations')
and hrcd.transaction_id(+)=hth.transaction_id
and papf.person_number IN ('901626', '900723', '900846');
Which is giving below result
Now I am Person 900846 has multiple rows coming, now I need to extract the max date from this column for that I added the below logic but this is not working
select papf.person_number, to_char(hrcd.SUBMITTED_DATE, 'DD-Mon-YYYY','NLS_DATE_LANGUAGE = American') as "Resignation Date", paam.last_update_date as assignmentupdate, hrcd.last_update_date as hrcdupdate, hth.last_update_date as hthupdate
from
per_all_people_f papf, per_all_assignments_m paam, hrc_txn_header hth, HRC_TXN_DATA hrcd
where
papf.person_id=paam.person_id
and paam.assignment_type IN ('E','C')
and paam.assignment_status_type in ('ACTIVE')
and paam.primary_flag = 'Y'
and paam.EFFECTIVE_LATEST_CHANGE ='Y'
and trunc(sysdate) between trunc(paam.effective_start_date) and trunc(paam.effective_end_date)
and trunc(sysdate) between trunc(papf.effective_start_date) and trunc(papf.effective_end_date)
and paam.person_id=hth.subject_id(+)
and paam.assignment_id=hth.object_id(+)
and hth.module_identifier(+) IN ('Resignation','Terminations')
and hrcd.transaction_id(+)=hth.transaction_id
and hrcd.SUBMITTED_DATE =
(SELECT MAX(hrcd2.SUBMITTED_DATE)
FROM HRC_TXN_DATA hrcd2, hrc_txn_header hth2, per_all_assignments_m paam2
WHERE hrcd2.TRANSACTION_ID = hrcd.TRANSACTION_ID
AND hrcd2.transaction_id=hth2.transaction_id
and hth2.module_identifier IN ('Resignation','Terminations')
and paam2.assignment_id=hth2.object_id
and paam2.assignment_id=paam.assignment_id
)
and papf.person_number IN ('901626', '900723', '900846');
But now the Output is like below
I am not sure how the outer join will be added in the second query and even after after that the result should 3 lines of data each for employee with max resignation date and blank is resignation date is null
Output should look like below
can someone help me in this?
Thanks,
Shivam

Answer 1

You can use window functions (ROW_NUMBER | RANK | DENSE_RANK | MAX OVER) to rank your rows and only pick the latest per person. E.g.:
select person_number, "Resignation Date", assignmentupdate, hrcdupdate, hthupdate
from
(
select
papf.person_number,
to_char(hrcd.submitted_date, 'DD-Mon-YYYY', 'NLS_DATE_LANGUAGE = American') as "Resignation Date",
paam.last_update_date as assignmentupdate,
hrcd.last_update_date as hrcdupdate,
hth.last_update_date as hthupdate,
hrcd.submitted_date,
max(hrcd.submitted_date) over (partition by papf.person_number) as max_submitted_date
from per_all_people_f papf
join per_all_assignments_m paam on paam.person_id = papf.person_id
left join hrc_txn_header hth on hth.subject_id = paam.person_id
and hth.object_id = paam.assignment_id
and hth.module_identifier IN ('Resignation', 'Terminations')
left join HRC_TXN_DATA hrcd on hrcd.transaction_id = hth.transaction_id
where papf.person_number IN (901626, 900723, 900846)
and paam.assignment_type IN ('E', 'C')
and paam.assignment_status_type in ('ACTIVE')
and paam.primary_flag = 'Y'
and paam.effective_latest_change = 'Y'
and trunc(sysdate) between trunc(paam.effective_start_date) and trunc(paam.effective_end_date)
and trunc(sysdate) between trunc(papf.effective_start_date) and trunc(papf.effective_end_date)
)
where (submitted_date = max_submitted_date)
or (submitted_date is null and max_submitted_date is null)
order by person_number;