使用聚合函数和算术运算

Question

我有一个包含两列的表

这里我需要根据以下函数找到一个SQL，

Z = accelx-AVG(accelx) for every rows. 

Answer 1

这通常使用AVG的分析版本来完成：

select accelx - avg(accelx) over ()
from mytable;

Answer 2

只需在子查询中计算AVG：

SELECT AccelX - (SELECT AVG(AccelX) FROM T)
FROM T

Answer 3

试试这个：

select t1.accelx - t2.avgx as Z
from TableName as t1
inner join (
    select avg(accelx) as avgx
    from TableName
    ) as t2
on 1 = 1

Answer 4

SELECT t1.accelx - t2.avgx as Z, userName 
FROM TableName as t1
JOIN (SELECT userName, avg(accelx) as avgx
      FROM TableName
      GROUP BY userName) as t2       
  ON t1.userName = t2.userName

Answer 5

MSSQL Server上的TSQL具有Windowed功能。 OVER Clause

SELECT 
    [AccelX]
    ,[AccelX] - AVG([AccelX]) OVER ()
FROM T