上周与两周前的 MYSQL 每日数据比较

Question

我有多个地点的每日数据，我们需要将上周的总销售额与两周前的总销售额进行比较。这是MYSQL代码

SELECT
    name,
    SUM(CASE WHEN WEEK(date) = WEEK(now())-1 THEN sales ELSE NULL END) as 'Last Week',
    SUM(CASE WHEN WEEK(date) = WEEK(now())-2 THEN sales ELSE NULL END) as '2 Weeks Ago',
    SUM('1week' - '2week') AS 'Change'
FROM daily_sales
GROUP BY name

第一三列的输出是正确的，但我无法正确计算第四列的“变化”。尝试了 SUM 的案例，但无法克服无效的使用 og 组功能：

SUM((SUM(CASE WHEN WEEK(date) = WEEK(now())-1 THEN sales ELSE NULL END)) 
- (SUM(CASE WHEN WEEK(date) = WEEK(now())-2 THEN sales ELSE NULL END))) AS 'change'

救命！

Answer 1

你快到了；只需采用给出第 2 列和第 3 列的公式并在它们之间加上一个减号：

SELECT 
  name, 
  SUM(CASE WHEN WEEK(date) = WEEK(now())-1 THEN sales END) as LastWeek, 
  SUM(CASE WHEN WEEK(date) = WEEK(now())-2 THEN sales END) as TwoWeeksAgo,
  SUM(CASE WHEN WEEK(date) = WEEK(now())-1 THEN sales END) - SUM(CASE WHEN WEEK(date) = WEEK(now())-2 THEN sales END) as change
FROM daily_sales
WHERE date >= date_sub(now(), interval 3 week)
GROUP BY name

或者通过使用子查询：

SELECT name, lastweek, twoweeksago, lastweek - twoweeksago as change
FROM
(
 SELECT 
  name, 
  SUM(CASE WHEN WEEK(date) = WEEK(now())-1 THEN sales END) as LastWeek, 
  SUM(CASE WHEN WEEK(date) = WEEK(now())-2 THEN sales END) as TwoWeeksAgo
 FROM daily_sales
 WHERE date >= date_sub(now(), interval 3 week)
 GROUP BY name
) x

或者通过使用 cte：

WITH x AS(
 SELECT 
  name, 
  SUM(CASE WHEN WEEK(date) = WEEK(now())-1 THEN sales END) as LastWeek, 
  SUM(CASE WHEN WEEK(date) = WEEK(now())-2 THEN sales END) as TwoWeeksAgo
 FROM daily_sales
 WHERE date >= date_sub(now(), interval 3 week)
 GROUP BY name
)

SELECT name, lastweek, twoweeksago, lastweek - twoweeksago as change