Can i use partition by for the following

Question

hi, i wanted to find out if i can use partition by or rank to the get the needed results below. If yes can anyone help me out with it.
if there is an other way to get the results also please let me know.
i'm using Oracle version 10.2.0.4.0
create table script:
CREATE TABLE DMM.QUES
  CASENAME        VARCHAR2(100 BYTE),
  CASENUMBER      VARCHAR2(20 BYTE),
  COVERAGE        VARCHAR2(10 BYTE),
  DIVISIONNUMBER  VARCHAR2(6 BYTE),
  CLASSNUMBER     number,
  TIER            VARCHAR2(2 BYTE),
  MONTHLYRATE     NUMBER
  )Insert statement scripts:
insert into QUES (CASENAME,CASENUMBER,  COVERAGE,  DIVISIONNUMBER,  CLASSNUMBER,  TIER,MONTHLYRATE)
values ('ABC','123J','health', '456J','987',null,.25)
insert into QUES (CASENAME,CASENUMBER,  COVERAGE,  DIVISIONNUMBER,  CLASSNUMBER,  TIER,MONTHLYRATE)
values ('ABC','123J','health', '456J','123',null,.25)
insert into QUES (CASENAME,CASENUMBER,  COVERAGE,  DIVISIONNUMBER,  CLASSNUMBER,  TIER,MONTHLYRATE)
values ('ABC','123J','health', '456J','453',null,.25)
insert into QUES (CASENAME,CASENUMBER,  COVERAGE,  DIVISIONNUMBER,  CLASSNUMBER,  TIER,MONTHLYRATE)
values ('ABC','123J','dental', '456J','453','ee',.29)
insert into QUES (CASENAME,CASENUMBER,  COVERAGE,  DIVISIONNUMBER,  CLASSNUMBER,  TIER,MONTHLYRATE)
values ('ABC','123J','dental', '456J','453','es',.23)
insert into QUES (CASENAME,CASENUMBER,  COVERAGE,  DIVISIONNUMBER,  CLASSNUMBER,  TIER,MONTHLYRATE)
values ('ABC','123J','dental', '456J','453','ec',.44)
insert into QUES (CASENAME,CASENUMBER,  COVERAGE,  DIVISIONNUMBER,  CLASSNUMBER,  TIER,MONTHLYRATE)
values ('ABC','123J','dental', '456J','453','fa',.33)
insert into QUES (CASENAME,CASENUMBER,  COVERAGE,  DIVISIONNUMBER,  CLASSNUMBER,  TIER,MONTHLYRATE)
values ('ABC','123J','dental', '456J','123','ee',.45)
insert into QUES (CASENAME,CASENUMBER,  COVERAGE,  DIVISIONNUMBER,  CLASSNUMBER,  TIER,MONTHLYRATE)
values ('ABC','123J','dental', '456J','123','es',.45)
insert into QUES (CASENAME,CASENUMBER,  COVERAGE,  DIVISIONNUMBER,  CLASSNUMBER,  TIER,MONTHLYRATE)
values ('ABC','123J','dental', '456J','123','ec',.46)
insert into QUES (CASENAME,CASENUMBER,  COVERAGE,  DIVISIONNUMBER,  CLASSNUMBER,  TIER,MONTHLYRATE)
values ('ABC','123J','dental', '456J','123','fa',.49)select * from ques:
ABC     123J     health     456J     987          0.25
ABC     123J     health     456J     453          0.25
ABC     123J     health     456J     123          0.25
ABC     123J     dental     456J     453     ee     0.29
ABC     123J     dental     456J     453     es     0.23
ABC     123J     dental     456J     453     ec     0.44
ABC     123J     dental     456J     453     fa     0.33
ABC     123J     dental     456J     123     ee     0.45
ABC     123J     dental     456J     123     es     0.45
ABC     123J     dental     456J     123     ec     0.46
ABC     123J     dental     456J     123     fa     0.49i would like to get the following output
ABC     123J     health     456J     123          0.25
ABC     123J     dental     456J     123     ee     0.45
ABC     123J     dental     456J     123     es     0.45
ABC     123J     dental     456J     123     ec     0.46
ABC     123J     dental     456J     123     fa     0.49i would like the code to take the minimum of classnumber for each divisonnumber/coverage combination and give me all the records for that classnumber.
Thanks in advance.

Answer 1

Hi,
That's an example of a Top-N Query , and yes, analytic functions are a good way to do it:
WITH     got_r_num     AS
     SELECT     ques.*
     ,     RANK () OVER ( PARTITION BY  coverage
                           ,          divisionnumber
                      ORDER BY          classnumber
                    ) AS r_num
     FROM    ques
SELECT  casename, casenumber, coverage, divisionnumber, classnumber, tier, monthlyrate
FROM     got_r_num
WHERE     r_num     = 1
;Thanks for posting the CREATE TABLE and INSERT statements, that's very helpful!
"PARTITION BY" is a clause often used with analytic functions. "PARTTIION" also means at least two other things in Oracle, so people will understand you better if you say "analytic functions", rather than "partition by".
For more about the RANK function, see this thread:
Re: A "double grouping" SQL query