如何在 CASE 语句中创建多个可能重叠的条件并使用 GROUP BY

Question

我在 BigQuery 中有一个查询：

WITH
  date_params AS(
  SELECT
    DATE_TRUNC(DATE_ADD(CURRENT_DATE(), INTERVAL -7 day), WEEK(MONDAY)) AS WeekStartDate,
    DATE_TRUNC(DATE_ADD(CURRENT_DATE(), INTERVAL -1 day), WEEK(SUNDAY)) AS WeekEndDate,
    date "2020-01-01" AS ReportStartDate,
    ),
  finances AS (
  SELECT
    Amount,
    CASE
      WHEN DATE (t1.Created ) BETWEEN WeekStartDate AND WeekEndDate THEN "Weelky"
      WHEN DATE (t1.Created ) BETWEEN ReportStartDate
    AND WeekEndDate THEN "Cumulative"
  END
    AS ReportPeriod
  FROM
    Table_1 t1,
    date_params p )
SELECT
  SUM(Amount) AS `Amount`
FROM
  finances
GROUP BY
  ReportPeriod

您能否解释一下如何在两个时间段之间对结果金额进行分组：1）上周和 2）从某个日期（ReportStartDate）开始，就像我尝试做的那样。唯一的问题是“累积”的 CASE 语句包括“Weelky”中的日期，但我需要从 ReportStartDate 到上周日，包括上周。

Answer 1

CASE 只会为每一行返回一个值，这就是Weelky 中包含的行不包含在Cumulative 中的原因。有多种方法可以使单个行在两个报告中都可用。我认为可以更好地保留现有查询结构的方法如下，它构造了一个 array 以便能够用多个报告标记单行，然后是 unnests 数组。我希望这对你有用！

WITH
  date_params AS(
  SELECT
    DATE_TRUNC(DATE_ADD(CURRENT_DATE(), INTERVAL -7 day), WEEK(MONDAY)) AS WeekStartDate,
    DATE_TRUNC(DATE_ADD(CURRENT_DATE(), INTERVAL -1 day), WEEK(SUNDAY)) AS WeekEndDate,
    date "2020-01-01" AS ReportStartDate,
    ),
  finances AS (
  SELECT
    Amount,
    ARRAY_CONCAT(
      IF (DATE (t1.Created) BETWEEN WeekStartDate AND WeekEndDate,["Weelky"],[]),
      IF (DATE (t1.Created) BETWEEN ReportStartDate AND WeekEndDate,["Cumulative"],[])
    ) as ReportPeriod
  FROM
    Table_1 t1,
    date_params p )
SELECT
  SUM(Amount) AS `Amount`
FROM
  finances
  CROSS JOIN unnest(ReportPeriod) as ReportPeriod
GROUP BY
  ReportPeriod

Answer 2

您可以从 ReportStartDate 开始“累积”并在 WeekStartDate 之前结束。

CASE 
    WHEN DATE (t1.Created ) BETWEEN WeekStartDate
           AND WeekEndDate then "Weelky"
    WHEN DATE (t1.Created ) BETWEEN ReportStartDate
           AND WeekStartDate-1 then "Cumulative"
    END 
    AS ReportPeriod