Need better alternative to this query

Question

I have a table A.
Table A
X Y
1 R
2 R
3 R
3 S
4 R
4 S
5 P
5 S
I want the result as follows ( record which has Y equals to R or S but if it has both R and S then just get the one with Y equals to R)
X Y
1 R
2 R
3 R
4 R
5 S
So my query is
Select * From A
Where Y = 'R'
UNION
SELECT * FROM TEST WHERE X IN(
Select X From Test
Minus
Select X From Test
Where Y = 'R'
AND Y = 'S';
It will get me the correct result but I feel there must be some other way that is much better than this query.
Thanks,
Sam

Answer 1

with sample_data as (
     select 1 x, 'R' y from dual union all
     select 1, 'R' from dual union all
     select 2, 'R' from dual union all
     select 3, 'R' from dual union all
     select 3, 'S' from dual union all
     select 4, 'R' from dual union all
     select 4, 'S' from dual union all
     select 5, 'P' from dual union all
     select 5, 'S' from dual)
select
x
,max(y) keep (dense_rank first order by y) y
from sample_data
where
y in ('R','S')
group by
x
order by
x
X Y
1 R
2 R
3 R
4 R
5 S It slightly more verbose than blue's solution, but gives you some more possibilites to influence the order than the simple max if necessary (e.g. NLS_SORT)
You want an example, wont you;-)
with sample_data as (
     select 1 x, 'R' y from dual union all
     select 1, 'R' from dual union all
     select 2, 'R' from dual union all
     select 3, 'r' from dual union all
     select 3, 'S' from dual union all
     select 4, 'R' from dual union all
     select 4, 'S' from dual union all
     select 5, 'P' from dual union all
     select 5, 'S' from dual)
select
x
,min(y) my
,max(y) keep (dense_rank first order by nlssort(y,'NLS_SORT=LATIN')) y
from sample_data
where
y in ('R','S','r')
group by
x
order by
x
X MY Y
1 R R
2 R R
3 S r
4 R R
5 S S Edited by: chris227 on 14.09.2012 07:10