Analytical function Query

Question

Hi,
I have below query with mentioned table and data setup. I always want the specific value (in this case 'CAR' or 'BIKE') record as result of this query and if i pass 'ALL' i need that record.
So I use decode function and convert the 'ALL' value to NULL and made it to go last. so on the top always the specific value records will come and from the outer query i can get the 1st record alone.
But the problem is when i run the inner query it works fine but along with outer query I am getting 'ALL' record as the result.
My question is : is the ROW_NUMBER() fuction alias doesn't have scope outside of the inner query.
Note : if i use rownum = 1 instead of rrn=1 it works fine.
Is there anyother alternate solution or any bug in this query.
Table1
col1 col2
A CAR
A BIKE
B ALL
Query:
SELECT indicator
FROM (SELECT indicator, ROW_NUMBER() OVER( ORDER BY DECODE(col2, 'ALL', NULL) asc NULLS LAST) rrn
FROM table1
WHERE (col2 = <Input specific value>
OR col2 = 'ALL')
WHERE rrn = 1;
Thanks in advance.

Answer 1

you did not excatly what you ment to do:
Naga wrote:
So I use decode function and convert the 'ALL' value to NULL and made it to go last.You only specified the decode for 'ALL', but said nothiung about the other values. So just add a default.
with table1 as (
select 'A' col1, 'CAR' col2 from dual union all
select 'A', 'BIKE' from dual union all
select 'B', 'ALL' from dual )
SELECT col1
FROM (
SELECT col1, ROW_NUMBER() OVER( ORDER BY DECODE(col2, 'ALL', NULL, 1) asc NULLS LAST) rrn
FROM table1
WHERE (col2 = 'CAR'
OR col2 = 'ALL')
WHERE rrn = 1
COL1
A    The "scope" of the row_number() is stable, so you can refer to it from the outer query.
regards chris