google-bigquery - google-bigquery 中过去 12 个月的聚合

Question

如何在 WHERE 子句中汇总过去 12 个月 (TTM) 的总使用 CASE 语句？谷歌大查询

这是我的查询...

SELECT
  clientid,
  clientname,
  year(revrecdate)*100 + month(revrecdate) as Period, *** NAMES the TTM period
  count(revrecdate) as Jobs,
  sum(profit) as Profits
FROM 
  oiafd.JobProfit
WHERE
  revrecdate >= '2010-12-01 00:00:00'
  and clientid = '2KOOLPDX'
  and CASE  WHEN month(revrecdate) = 1
            THEN(revrecdate <= timestamp(concat(string(year(revrecdate)),'-01-31')) and 
              revrecdate >= timestamp(concat(string(year(revrecdate)-1),'-02-01')))
            WHEN month(revrecdate) = 2
            THEN(revrecdate <= timestamp(concat(string(year(revrecdate)),'-02-28')) and 
              revrecdate >= timestamp(concat(string(year(revrecdate)-1),'-03-01')))

Answer 1

要回答有关将 CASE 语句的概念转换为适用于 BigQuery 的内容的问题：您可以使用 IF 函数将每个案例分解为 WHERE 中的单独子句。

像这样的东西会起作用：

...
WHERE
  revrecdate >= '2010-12-01 00:00:00'
  and clientid = '2KOOLPDX'
  and IF(month(revrecdate) = 1,
         revrecdate <= timestamp(concat(string(year(revrecdate)),'-01-31')) and 
         revrecdate >= timestamp(concat(string(year(revrecdate)-1),'-02-01')),
         true)
  and IF(month(revrecdate) = 2,
         revrecdate <= timestamp(concat(string(year(revrecdate)),'-02-28')) and 
         revrecdate >= timestamp(concat(string(year(revrecdate)-1),'-03-01')),
         true)

有关 IF() 的详细信息，请参阅https://developers.google.com/bigquery/query-reference#otherfunctions。