Simple SQL select sum one time and values of same column

Question

I have create this query:

SELECT table1.id, b.sum 
FROM table1 
CROSS JOIN (SELECT SUM(id) sum 
            FROM table1) b 
ORDER BY id DESC;

But this produces results like this:

id	sum
3	6
2	6
1	6

Sum value print only one time. Can you help me.

But I want this result :

id	sum
3	6
2
1

Answer 1

This should do it:

select 
   id,
   CASE WHEN id=(max(id) over()) 
        THEN sum(id) over (order by id) END as 'sum' 
from cte1
order by id desc;

more info see: Window Function Concepts and Syntax