在 bigquery 中的最后提取日期计算未来 18 个月的预测

Posted 2023-03-25

【中文标题】在 bigquery 中的最后提取日期计算未来 18 个月的预测

【英文标题】：calculate forecast for next 18 months on last extract date in bigquery

【发布时间】：2018-01-19 11:35:13

【问题描述】：

我想根据最后提取日期（每个星期一）检查未来 18 个月的预测数量。如果最后提取日期是 2018 年 3 月，则应从 2018 年 3 月开始计算未来 18 个月。

我在 bigquery 中尝试了以下案例语句，但它应该将上周一日期作为提取日期（extract_date），并根据材料名称（材料）和交货日期（交付日期）提供接下来 6、12、18 个月的数量总和

SELECT
  material,
  material_desc,
  extract_date, 
  deliv_date,
  SUM(quantity) AS quantity, 
  CASE
      WHEN 
      (MONTH(deliv_date)=1 AND year(deliv_date)=2018) OR
      (MONTH(deliv_date)=2 AND year(deliv_date)=2018) OR 
      (MONTH(deliv_date)=3 AND year(deliv_date)=2018) OR 
      (MONTH(deliv_date)=4 AND year(deliv_date)=2018) OR 
      (MONTH(deliv_date)=5 AND year(deliv_date)=2018) OR 
      (MONTH(deliv_date)=6 AND year(deliv_date)=2018) OR 
      (MONTH(deliv_date)=7 AND year(deliv_date)=2018) THEN '6months' 

      WHEN 
      (MONTH(deliv_date)=1 AND year(deliv_date)=2018) OR
      (MONTH(deliv_date)=2 AND year(deliv_date)=2018) OR 
      (MONTH(deliv_date)=3 AND year(deliv_date)=2018) OR 
      (MONTH(deliv_date)=4 AND year(deliv_date)=2018) OR 
      (MONTH(deliv_date)=5 AND year(deliv_date)=2018) OR 
      (MONTH(deliv_date)=6 AND year(deliv_date)=2018) OR 
      (MONTH(deliv_date)=7 AND year(deliv_date)=2018 ) OR 
      (MONTH(deliv_date)=8 AND year(deliv_date)=2018) OR 
      (MONTH(deliv_date)=9 AND year(deliv_date)=2018) OR 
      (MONTH(deliv_date)=10 AND year(deliv_date)=2018) OR 
      (MONTH(deliv_date)=11 AND year(deliv_date)=2018) OR 
      (MONTH(deliv_date)=12 AND year(deliv_date)=2018) THEN '12Months' 
and same code for 18 months...
      ELSE NULL END AS Forecast_18_months 
      FROM table 
      GROUP BY
      material,
      material_desc,
      extract_date,
      deliv_date,
      Forecast_18_months

【参考方案1】：

这是一个粗略的想法。请参阅 Bigquery SQL 指南并对其进行修改以适合您的用例。

SELECT
  material
  forcast
  SUM(quantity)
FROM
  (
  SELECT 
    material
    CASE 
      WHEN DATE_DIFF(deliv_date, extract_date, MONTH) <= 6 THEN '6months'
      ELSE 'blabla'
    END AS forecast
    quantity
  FROM
    table
  )
GROUP BY
  material
  forecast

【讨论】：

我们如何计算 18 个月的日期差异？

只需添加更多 WHEN 语句即可检查长达 18 个月的不同案例。