a sql question

Hi,

Oracle 10g.
I have a table with data like this:

id val
1 100
2 101
3 200
4 300

and I want a query which displays the result of "val" minus the "previous val", order by id, something like:

id computed_value

2       1
3       99
4       100

How do I accomplish that using sql (not pl/sql)?

TIA
Guang Received on Mon Mar 05 2007 - 16:36:03 CST