Hello All

I have a requirement where i need to fetch only one record for the id provided.
If the id is present in the table it will fetch that particular record and if it is not present , it will fetch the NULL valued record

Example
Table-: demo_table

id
----
1
2
3
4
5
(null)

For example if i am passing id as 1 it should return only 1st row, similarly If i am passing id as 4 it should fetch only 4th row but if I am passing id that is not there in the table, it should give me the 6th record i.e. NULL valued record.

I want this to be in Single SQL query. Thanks for your help in advance.
Let me know if you need more information.

set feed on
set null <null>
var v number;

exec :v := 1;

with rws as (
  select rownum x from dual connect by level <= 5
  union all
  select null x from dual
), vals as (
  select * from rws
  where  x = :v or x is null
  order  by x nulls last
)
  select * from vals
  where  rownum = 1;

X  
1  


 1 rows selected
  
exec :v := 6;

with rws as (
  select rownum x from dual connect by level <= 5
  union all
  select null x from dual
), vals as (
  select * from rws
  where  x = :v or x is null
  order  by x nulls last
)
  select * from vals
  where  rownum = 1;
  
X       
<null>  


 1 rows selected