MAX function in OBIEE

Question

Hi All
My problem can be summarised as follows:
I have an hr table that stores person information. I am then using this table in my reports. The issue is that
a person can have more than record in the table and because I need to select the latest record for the person, only one record
must be selected. The thing is, by some inherent logic in which the table was developed, the only way the latest record for a person can be selected
is by taking the MAX(SURRO_PERSON_ID) for that person (surrogate key is the primary key for the table and is populated by a sequence, so the max will give the latest record
for that person)
I am creating a complex join in the RPD and since aggregate functions like MAX cannot be used in the expression builder in the RPD, I want to know
if there is a way by which I can achieve this. It would be nice if I could do it in the RPD itself instead of in Answers, but if there is no other way
then it is fine.
Please let me know if you need any more info.
Thanks a lot.

Answer 1

Hi.
As I unerstood the PERSON table has PERSON_ID as primary key. PERSON_INFORMATION table
has many records for one person or per one PERSON_ID so the PERSON_ID is foreign key to PERSON table
and SURRO_PERSON_ID is sequence (PK).
Do this:
View is just select parsed to a database (it's not really a view deployed in database).
Your view PERSON_INFORMATION_V will be something like:
select pi.surro_person_id,
pi.person_id,
pi.*
from person_information pi
where pi.surro_person_id in
(select max(pi.surro_person_id)
from person_information where person_id=pi.person_id)
Of course, you need to put all columns that you need, in the select part.
Now you create FK join from view to a PERSON table in physical layer:
PERSON_INFORMATION_V.PERSON_ID=PERSON.PERSON_ID
One person can have only one row in PERSON_INFORMATION_V.
In the BMM you need to create 2 logical tables.
One is for fact table and second for PERSON table.
In the BMM make complex join between PERSON logical table and fact logical table (before that make FK join between these
two tables in the physical layer PERSON.PERSON_ID=FACT.PERSON_ID).
In the PERSON logical table you will have only one logical table source (PERSON table) and inside it in general tab you
need to add physical table PERSON_INFORMATION_V and physical join to it, you can do this because one person has only one person information.
So in BMM you have one FACT and one dimension (PERSON with PERSON_INFORMATION_V snowflaked inside it.
Hope this helps.
Regards
Goran
http://108obiee.blogspot.com