我有一个像这样的SQL 2008数据库表
name score
-----------------------
steve 207
steve 205
steve 200
steve 139
我希望得到行之间的差异。 eqn = [row - (row + 1)] 所以我理想的是希望它成为,
steve 2 //207 - 205
steve 5 //205 - 200
steve 61 //200 - 139
steve 139 //139 - 0
最好的方法是什么? 谢谢!
答案 0 :(得分:17)
这是一种方法
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
答案 1 :(得分:6)
另一种方法是使用lag():
SELECT
name,
score - coalesce(lag(score) over (partition by name order by id), 0)
FROM table
ORDER BY name, id
TSQL中的lag()函数doesn't seem to be available,但在注释中建议使用此解决方法:
select name,
score - coalesce(
MIN(score) OVER (PARTITION BY name ORDER BY id
ROWS BETWEEN 1 PRECEDING AND 1 PRECEDING)
, 0) as diff
from table
order by name, id