Question

I have a SQL 2008 database table like this

name      score
-----------------------
steve     207
steve     205
steve     200
steve     139

I want to get the difference between the rows. eqn = [row – (row + 1)]
so I would ideally want it to be,

steve 2   //207 - 205
steve 5   //205 - 200
steve 61  //200 - 139
steve 139 //139 - 0

What is the best way to do this?
Thanks!

Answer 1

This is one way to do it

with cte as
(SELECT
   ROW_NUMBER() OVER (PARTITION BY table.name ORDER BY id) row,
   name,
   score
 FROM table)
SELECT 
   a.name ,
   a.score - ISNULL(b.score,0)
FROM
   cte a
   LEFT  JOIN cte b
   on a.name = b.name
    and a.row = b.row+1