Oracle 11g - Creating a side by side comparison of table comlumn data - sql

Question

I have a query where I need to extract data in a regular table and put two rows of data into a single row.
I have rows that consist of
StudentID AUDIT_ACTN Audit_Date .....
aaa A 01/01/2010
aaa A 03/04/2011
aaa A 02/02/2013
aaa D 09/10/2010
aaa D 05/06/2011
aaa D 06/07/2013
aaa A 11/12/2014~
bbb A 01/01/2010
bbb A 03/04/2011
bbb A 02/02/2013
bbb D 09/10/2010
bbb D 05/06/2011
bbb D 06/07/2013
bbb A 11/12/2014~
I want output like this
StudentID AUDIT_ACTN Audit_Date StudentID AUDIT_ACTN Audit_Date
aaa A 01/01/2010 aaa D 09/10/2010
aaa A 03/04/2011 aaa D 05/06/2011
aaa A 02/02/2013 aaa D 06/07/2013
aaa A 11/12/2014 NULL NULL NULL
bbb A 01/01/2010 bbb D 09/10/2010
bbb A 03/04/2011 bbb D 05/06/2011
bbb A 02/02/2013 bbb D 06/07/2013
bbb A 11/12/2014 NULL NULL NULL
The A & D data rows are related, a= add the something to the record and d = delete something from the record (something is an indicator). These is logical in that you must add something before you delete it and you cannot add it twice, without deleting it first.
My current script is probably going down the wrong track but here goes;
select a.StudentId,a.Audit_Date,a.AUDIT_ACTN,d.StudentId,Audit_Date,d.AUDIT_ACTN,
from table a
join
(select *
from
(Select StudentId, Audit_Date,AUDIT_ACTN
from table b
Where b.AUDIT_ACTN='D'
order by Audit_Date
)
where rownum=1
) d on a.StudentId = d.StudentId
and a.AUDIT_ACTN='A'
and Select * from (Select Audit_Date
Order by a.StudentId, a.Audit_Date
I know this is wrong but where do I go from here. If anyone can help and point me in the right direction. It would be appreciated.
My current attempts bring me zero rows, when I take out the rownum it brings me a x join returning 12 rows in this case.
thanks
Roger

Answer 1

I think you need aggregate function like below
select
A.StudentId,A.Audit_Date,A.AUDIT_ACTN,
D.StudentId,D.Audit_Date,D.AUDIT_ACTN
from
(Select StudentId, Audit_Date,AUDIT_ACTN,ROW_NUMBER()
OVER (PARTITION BY StudentId order by audit_date) rn
from table b
Where b.AUDIT_ACTN='D'
) D
FULL OUTER JOIN
(Select StudentId, Audit_Date,AUDIT_ACTN,ROW_NUMBER()
OVER (PARTITION BY StudentId order by audit_date) rn
from table b
Where b.AUDIT_ACTN='A'
) A
on A.rn = D.rn and A.StudentId = B.StudentId
I hope this will work