Correction in query using rank

Question

Hi All,
I have a sample table as below:
CREATE TABLE sample_obj (appno VARCHAR2(10),universe VARCHAR2(100),rank_univers NUMBER,country VARCHAR2(100),industrie VARCHAR2(10));
insert into sample_obj (APPNO, UNIVERSE, RANK_UNIVERS, COUNTRY, INDUSTRIE)
values ('E001', 'RE', 1, 'US', 'PS');
insert into sample_obj (APPNO, UNIVERSE, RANK_UNIVERS, COUNTRY, INDUSTRIE)
values ('E002', 'RM', 2, '', 'PD');
I have written the following query which orders the recods by rank_univers
SELECT country,
     industrie,
     rank() over(ORDER BY rank_univers) rank_univ
FROM sample_obj;
Result set :
COUNTRY     INDUSTRIE     RANK_UNIV
US     PS     1
     PD     2
I need the result set to have only the record that has non null values of COUNTRY and INDUSTRIE. Here above, I need only US,PS,1 record.
If for both the records, either all the values for COUNTRY and INDUSTRIE are either null or not null, then i should get records as per the rank_univ.
CASE 1:
If the records both have COUNTRY AND INDUSTRI not null then I should get only
RANK_UNIV=1 record.
CASE 2:
If for any of the records either COUNTRY or INDUSTRIE is null , then record that has the not null value has to be chosen.
Can anyone help me out?
Thanks

Answer 1

Having re-read your question I think I now understand (it was a little cryptic to understand :-) ).
If both country and industrie are not null, that have high priority.
If country is not null and industrie is null, that have medium priority.
If country is null and industrie is not null, that have medium priority.
If both country and industrie are null, that have low priority.
That can also be included in the CASE logic:
SELECT
country,
industrie,
rank() over(
  ORDER BY
  case
    when country is not null and industrie is not null then 1
    when country is not null and industrie is null then 2
    when country is null and industrie is not null then 2
    else 3
  end,
  rank_univers
) rank_univ
FROM sample_obj;The CASE statement gives a priority for the ranking.
Then if there are more than one record with same priority, they are ordered by rank_univers.
Using such a method you can express practically any ranking/ordering logic in your order by clause.