SQL Select 1 line in function of 3 MAX/MIN fields - sql

Question

I try to create a view, or just a select for the moment, based on this function :
SELECT
FLAG
FROM
(
SELECT
TE.FLAG
FROM
EVT E
INNER JOIN EVT_TYP TE ON TE.ID = E.FK_TYPE_EVT
WHERE
E.FK_OBJECT = NUMOBJECT
order by
trunc(E.EVT_DATE) desc,
e.evt_number desc,
e.id desc
)
where
rownum = 1;
NUMOBJECT is the function parameter. Function returns one FLAG for that NUMOBJECT.
I want to select one flag for each E.FK_OBJECT IN EVT table.
Problems are I can have several lines in EVT table for one E.FK_OBJECT the same day, and I don't have time part of the date, most of the time. E.evt_number can be int or NULL. And E.id haven't the same order that E.EVT_DATE.
I don't know how I can succeed it, can you help me please? I try with imbricates select but looks likes it's not possible beacause of NULL e.evt_number.
I work on Oracle DB.
edit :
Sample of data :
Heberger image http://img15.hostingpics.net/thumbs/mini_229922Sanstitre.png
I tried this :
SELECT E.Fk_Object
,TE.FLAG
FROM (
SELECT
E.Fk_Object
,E.EVT_DATE
,E.evt_number
,MAX(E.id) id
FROM (
SELECT
E.Fk_Object
,E.EVT_DATE
,MAX(NVL(e.evt_number, - 1)) evt_number
FROM (
SELECT
E.Fk_Object
,MAX(E.EVT_DATE) EVT_DATE
FROM EVT E
GROUP BY E.Fk_Object
) E_MAX
INNER JOIN EVT E ON E.Fk_Object = E_MAX.Fk_Object
AND E.EVT_DATE = E_MAX.EVT_DATE
WHERE e.flg_suppression = 0
AND e.evt_date IS NOT NULL
GROUP BY E.Fk_Object
,E.EVT_DATE
) E_MAX_2
INNER JOIN EVT E ON E.Fk_Object = E_MAX_2.Fk_Object
AND E.EVT_DATE = E_MAX_2.EVT_DATE
AND NVL(e.evt_number, - 1) = NVL(E_MAX_2.evt_number, - 1)
GROUP BY E.Fk_Object
,E.EVT_DATE
,E.evt_number
) E_MAX_3
left JOIN EVT E ON E.Fk_Object = E_MAX_3.Fk_Object
AND E.EVT_DATE = E_MAX_3.EVT_DATE
AND NVL(e.evt_number, - 1) = NVL(E_MAX_3.evt_number, - 1)
AND E.id = E_MAX_3.id
INNER JOIN EVT_TYP TE ON TE.id = E.FK_EVT_TYP
ORDER BY 2
,3;
But it doesn't give me same results than function

Answer 1

Done !
Instead of NVL(E_MAX_2.evt_number, - 1) I have to use NVL(E_MAX_2.evt_number, 99) and not forget the trunc() for E.EVT_DATE to keep the same order than the function and it is ok !!
With that, it runs in 12 seconds. It was 54 before with the function.
I will test to create a view to see if it's even better.

Answer 2

If I understand correctly, you are looking for a query that gives you the latest flag for not only one, but several objects. You can do this by selecting records for all these objects and then grouping by object applying Oracle's KEEP FIRST/LAST.
select
e.fk_object,
max(te.flag) keep (dense_rank first
order by trunc(e.evt_date) desc, e.evt_number desc, e.id desc) as current_flag
from evt e
join evt_typ et on et.id = e.fk_type_evt
where fk_object in (numobject1, numobject2, numobject3)
group by e.fk_object;
The same can be used as a subquery. Let's say you have a table OBJECTS with a column STATUS and you want to show all objects of status 'new' with their current flag each:
select o.*, flags.current_flag
from objects o
join
(
select
e.fk_object,
max(te.flag) keep (dense_rank first
order by trunc(e.evt_date) desc, e.evt_number desc, e.id desc) as current_flag
from evt e
join evt_typ et on et.id = e.fk_type_evt
group by e.fk_object
) flags on flags.fk_object = o.id
where o.status = 'new';