将两列作为总数相加，然后将两个总数减去答案

【问题标题】：sum two columns as totals then minus the two totals together将两列作为总数相加，然后将两个总数减去
【发布时间】：2018-01-31 20:16:23
【问题描述】：

我有这个脚本：

SELECT

  ISNULL([name], 'Total') AS [name]
, [Yesterday]
, [Today]
, [variance]

FROM 
(
  SELECT 
[name],
SUM([yesterday]) AS [yesterday],
SUM([today]) AS [today],
sum(variance) as Variance

  FROM mytable
      GROUP BY [name] WITH ROLLUP
 ) AS DT

返回此表：

name  |yesterday|today|variance
john  | 3       |4    | 0.33
smith | 4       |5    |0.25
daniel| 5       |2    |-0.6
total | 12      |11   |-0.02

总方差实际上应该是：(11-12)/12 = -0.833

如何让我的脚本产生该结果而不是总方差列？

预期的数据是：

name  |yesterday|today|variance
john  | 3       |4    | 0.33
smith | 4       |5    |0.25
daniel| 5       |2    |-0.6
total | 12      |11   |-0.833

【问题讨论】：

您能否提供您期望给定结果的数据？
我已经更新了。一切基本保持不变，但需要正确计算一个数字。

标签： sql sql-server sum variance rollup

【解决方案1】：

你试过了吗？：

SELECT

  ISNULL([name], 'Total') AS [name]
, [Yesterday]
, [Today]
, [variance]

FROM 
(
  SELECT 
[name],
SUM([yesterday]) AS [yesterday],
SUM([today]) AS [today],
((SUM([today]) -SUM([yesterday]))/SUM([yesterday])) as Variance

  FROM mytable
      GROUP BY [name] WITH ROLLUP
 ) AS DT

【讨论】：

否，因为这将仅计算两列上的行，而不是返回查询底部的实际总数...