Fetch relevant rows based on condition using Oracle 12C

Question

I am trying to query the below data set :

Sample input :

create table t(sn varchar(100),easyrfqy varchar(10),ecaty int,ps varchar(10))
insert into t values('abc','NO',0,'E'),('abc','YES',1,'N'),('abc','NO',0,'W'),
('def','NO',1,'E'),('def','NO',0,'X'),('xyz','NO',1,'X')

Expected out :

sn easyrfqy_update ecaty_update ps

abc YES 1 Pref
abc YES 1 Pref
abc YES 1 Pref
def NO  1 Pref
def NO  1 Pref
xyz NO  1 NP

Logic Based : for a particular sn if easyrfqy ='P' or 'E' or 'N' then Pref for a particular sn if it has a ecaty 1 then set 1 for all rows for that sn for a particular sn if it had easyrfqy 'YES' then set all rows as YES

I tried this :

select * from
(
select *,row_number()over(partition by sn order by ecat desc) as rn from t
)x where x.rn=1

Here is the SQl fiddle : http://www.sqlfiddle.com/#!6/e104d/1

Answer 1

select t.sn,
       max(easyrfqy) over (partition by sn) as easyrfqy_update,
       max(ecaty) over (partition by sn) as ecaty_update,
       max(case when ps in ('P', 'E', 'N') then 'Pref' else 'NP' end) over (partition by sn) as ps
from t

It depends on the assumption that the string 'YES' is greater than 'NO' in the actual language environment the query is executed, and similarly 'Pref' > 'NP'. If it is not true for any reason, than more tricky approch is needed, eg:

decode(max(case when ps in ('P', 'E', 'N') then 1 else 0 end) over (partition by sn), 1, 'Pref', 0, 'NP') as ps