Query return data on prioritize basis

Question

Hi All
I have the following tables:
Create Table
CREATE TABLE PARENT_MST ( PARENT_LINE_TYPE VARCHAR2(30),
DETAIL_LINE_TYPE VARCHAR2(30));
CREATE TABLE MASTER_DTL ( DETAIL_ID NUMBER(5),
DETAIL_LINE_TYPE VARCHAR2(30));
Insert in Table
INSERT INTO PARENT_MST
(PARENT_LINE_TYPE,DETAIL_LINE_TYPE)
VALUES
('HEALTH','EH');
INSERT INTO PARENT_MST (PARENT_LINE_TYPE ,DETAIL_LINE_TYPE)
VALUES
('HEALTH','DRG');
INSERT INTO PARENT_MST (PARENT_LINE_TYPE,DETAIL_LINE_TYPE)
VALUES
('HEALTH', 'HOSE');
INSERT INTO PARENT_MST (PARENT_LINE_TYPE, DETAIL_LINE_TYPE)
VALUES
('HEALTH','VIS');
INSERT INTO MASTER_DTL
(DETAIL_ID,DETAIL_LINE_TYPE)
VALUES
(1,'HEALTH');
INSERT INTO MASTER_DTL
(DETAIL_ID,DETAIL_LINE_TYPE)
VALUES
(2,'DRG');
My requirement is that I have such kind of query in which system first check the DETAIL_LINE_TYPE in table MASTER_DTL and if that specific DETAIL_LINE_TYPE is exist then return it and if not exist in table MASTER_DTL then go to PARENT_MST and check with PARENT_MST.DETAIL_LINE_TYPE and if match then return its PARENT_LINE_TYPE but cannot repeat PARENT_LINE_TYPE .
For example:
in case for 'EH' system return 'HEALTH' because 'EH' is not exist in MASTER_DTL.DETAIL_LINE_TYPE.
in case 'DRG' system return DRG because DRG is exist in MASTER_DTL table
in case 'HOSE' system does not return 'HEALTH' because HEALTH already exist so query does not return any thing
in case 'VIS' system does not return 'HEALTH' because HEALTH already exist so query does not return any thing
My desire output is something like this:
DRG
HEALTH---------
I have the following query in my package and want to use the same query with some modification in my package. Is there any possibility that we can write desired code after column name like this:
select DETAIL_LINE_TYPE  (  some code here as per requirement   )
from MASTER_DTL
where DETAIL_LINE_TYPE
  in
  ('EH',
  'DRG',
  'HOSE',
  'VIS'
Existing Query
select DETAIL_LINE_TYPE
from MASTER_DTL
where DETAIL_LINE_TYPE
in
('EH',
'DRG',
'HOSE',
'VIS'
);

Answer 1

Thanks for the replies and accept my apology for not clarification things. Let me try to clear it in more detail.
I already have one query in my package that is below :
Query
select DETAIL_LINE_TYPE from MASTER_DTL
where DETAIL_LINE_TYPE
in
('EH',
'DRG',
'HOSE',
'VIS'
My requirement is that system first check the values in field MASTER_DTL.DETAIL_LINE_TYPE
by using the provided list that is ('EH', 'DRG', 'HOSE', 'VIS' ) and if value not find in table MASTER_DTL.DETAIL_LINE_TYPE then system check that value in other table that is PARENT_MST.DETAIL_LINE_TYPE and if system find the value then instead of returning PARENT_MST.DETAIL_LINE_TYPE value, system return corresponding PARENT_LINE_TYPE value but if the PARENT_LINE_TYPE already return then system does not return anything.
For example:
I have to process 4 DETAIL_LINE_TYPE ('EH', 'DRG', 'HOSE', 'VIS' ) .
First system try to search 'EH' in table MASTER_DTL.DETAIL_LINE_TYPE and if not found then try to search it in table PARENT_MST.DETAIL_LINE_TYPE and if found then return its corresponding PARENT_MST.PARENT_LINE_TYPE.
Same steps involved in 'HOSE', 'VIS' but in case of 'DRG' the query found DRG in table MASTER_DTL.DETAIL_LINE_TYPE and no need to check the value in PARENT_MST table. I think if I use distinct then I will not get duplicate records so for the time being ignore checking of duplication.
Please let me know if you have any question.
Regards
Shumail