ORACLE MAX GROUP BY - sql

Question

I am using Oracle (SQL Developer). Please find below the example and an outcome which would like to get (purpose of select is to find out people who submitted project A and have not done any activities in project B yet):
Data table:
CREATE TABLE "XXX"."TABLE1"
( "STATUS" VARCHAR2(20 BYTE),
"PROJECT_NAME" VARCHAR2(20 BYTE),
"VERSION_NUMBER" NUMBER,
"PERSON" VARCHAR2(20 BYTE)
);
Insert into XXX.TABLE1 (STATUS,PROJECT_NAME,VERSION_NUMBER,PERSON) values ('SUBMITTED','A','0','PETER');
Insert into XXX.TABLE1 (STATUS,PROJECT_NAME,VERSION_NUMBER,PERSON) values ('SUBMITTED','A','0','JOHN');
Insert into XXX.TABLE1 (STATUS,PROJECT_NAME,VERSION_NUMBER,PERSON) values ('SUBMITTED','A','1','JOHN');
Insert into XXX.TABLE1 (STATUS,PROJECT_NAME,VERSION_NUMBER,PERSON) values ('NEW','A','2','JOHN');
Insert into XXX.TABLE1 (STATUS,PROJECT_NAME,VERSION_NUMBER,PERSON) values ('SUBMITTED','A','0','MARY');
Insert into XXX.TABLE1 (STATUS,PROJECT_NAME,VERSION_NUMBER,PERSON) values ('SUBMITTED','B','0','PETER');
Insert into XXX.TABLE1 (STATUS,PROJECT_NAME,VERSION_NUMBER,PERSON) values ('NEW','B','1','PETER');
Insert into XXX.TABLE1 (STATUS,PROJECT_NAME,VERSION_NUMBER,PERSON) values ('SUBMITTED','B','0','JOHN');
Created table should look like this:
TABLE1:
TABLE1.STATUS TABLE1.PROJECT_NAME TABLE1.VERSION_NUMBER TABLE1.PERSON
SUBMITTED A 0 PETER
SUBMITTED A 0 JOHN
SUBMITTED A 1 JOHN
NEW A 2 JOHN
SUBMITTED A 0 MARY
SUBMITTED B 0 PETER
NEW B 1 PETER
SUBMITTED B 0 JOHN
Result what I want get is this:
STATUS PROJECT_NAME VERSION_NUMBER PERSON STATUS_1 PROJECT_NAME_1 VERSION_NUMBER_1 PERSON_1
SUBMITTED A 0 PETER NEW B 1 PETER
SUBMITTED A 1 JOHN SUBMITTED B 0 JOHN
SUBMITTED A 0 MARY
Select which I am using now is:
select t.*,v.*
from TABLE1 t
left outer join ( select u.*
from TABLE1 u
where exists (select max(z.VERSION_NUMBER)
,z.PERSON
,z.PROJECT_NAME
from TABLE1 z
where z.PROJECT_NAME = 'B'
and u.PROJECT_NAME = z.PROJECT_NAME
and u.PERSON = z.PERSON
group by z.PERSON, z.PROJECT_NAME
having u.VERSION_NUMBER = max(z.VERSION_NUMBER))) v
on t.PERSON = v.PERSON
where exists (select max (w.VERSION_NUMBER)
,w.PERSON
,w.PROJECT_NAME
from TABLE1 w
where w.PROJECT_NAME = 'A'
and w.STATUS = 'SUBMITTED'
and t.PROJECT_NAME = w.PROJECT_NAME
and t.PERSON = w.PERSON
group by w.PERSON, w.PROJECT_NAME
having t.VERSION_NUMBER = max (w.VERSION_NUMBER))
QUESTION: What would be best(right) way to write such select (best practice), should I better use Analytic functions or use something else instead of EXISTS?

Answer 1

I think you've over-complicated this...
WITH
project_status (status, project_name, version_number, person)
AS
(SELECT 'SUBMITTED','A','0','PETER' FROM dual UNION ALL
SELECT 'SUBMITTED','A','0','JOHN' FROM dual UNION ALL
SELECT 'SUBMITTED','A','1','JOHN' FROM dual UNION ALL
SELECT 'NEW','A','2','JOHN' FROM dual UNION ALL
SELECT 'SUBMITTED','A','0','MARY' FROM dual UNION ALL
SELECT 'SUBMITTED','B','0','PETER' FROM dual UNION ALL
SELECT 'NEW','B','1','PETER' FROM dual UNION ALL
SELECT 'SUBMITTED','B','0','JOHN' FROM dual
)
SELECT DISTINCT
ps.person
,ps.project_name
,ps.status
FROM
project_status ps
WHERE 1=1
AND ps.project_name = 'A'
AND ps.status = 'SUBMITTED'
AND NOT EXISTS
(SELECT 1
FROM project_status ps2
WHERE ps2.person = ps.person
AND ps2.project_name = 'B'
)
;

Answer 2

purpose of select is to find out people who submitted project A and
have not done any activities in project B yet
If your purpose is just to get the people, then you don't need the complete rows. One method to answer this is to use group by and having:
select t1.person
from "XXX"."TABLE1" t1
group by t1.person
having sum(case when project_name = 'A' and status = 'New' then 1 else 0 end) > 0 and
sum(case when project_name = 'B' then 1 else 0 end) = 0;
If you need the complete rows, then Christian has a reasonable solution.