自动转换日期以格式化 YYWW

Question

我需要将 2016 年最后一周的所有天按日期转换为 YYYYWW 格式。

#standardSQL
WITH Input AS (
  SELECT date
  FROM UNNEST([
    DATE '2016-12-26',
    DATE '2016-12-27',
    DATE '2016-12-28',
    DATE '2016-12-29',
    DATE '2016-12-30',
    DATE '2016-12-31',
    DATE '2017-01-01']) AS date
)

SELECT
  date,
  CAST(FORMAT_DATE('%Y%V', CAST(date AS DATE)) AS STRING) AS YearWeek,
  CAST(FORMAT_DATE('%Y', CAST(date AS DATE)) AS STRING) AS Year,
  CAST(FORMAT_DATE('%V', CAST(date AS DATE)) AS STRING) AS 
FROM Input 
ORDER BY date

一切正常，直到达到 2017-01-01:

Row date    YearWeek    Year    Week     
1   2016-12-26  201652  2016    52   
2   2016-12-27  201652  2016    52   
3   2016-12-28  201652  2016    52   
4   2016-12-29  201652  2016    52   
5   2016-12-30  201652  2016    52   
6   2016-12-31  201652  2016    52   
7   2017-01-01  201752  2017    52

'201752' 应该是 '201652'。

为历史日期自动化的最佳方式？

像这样：

IF (REGEXP_EXTRACT(date,r'\d{4}-\d{2}-(\d{2})') = CAST('01' AS STRING)
    AND Week = CAST('52' AS STRING), Year-1, Year)

Answer 1

%Y 将 return 日期的日历年而不是 ISO 年。对于 return ISO 年份，即 2017 年 1 月 1 日为 2016 年，请改用 %G。另见 Supported Format Elements for DATE。

Answer 2

以下适用于 BigQuery 标准 SQL

#standardSQL
WITH Input AS (
  SELECT DATE
  FROM UNNEST([
    DATE '2016-12-26',
    DATE '2016-12-27',
    DATE '2016-12-28',
    DATE '2016-12-29',
    DATE '2016-12-30',
    DATE '2016-12-31',
    DATE '2017-01-01']) AS date
)
SELECT
  date,
  FORMAT_DATE('%G%V', date) AS YearWeek  
FROM Input
ORDER BY date

另请注意 - 在您的示例中：
1. 你不需要 CAST(date AS DATE) 因为 date 已经是 DATE
类型 2. 你不需要 CAST(FORMAT_DATE(...) AS STRING) 因为 FORMAT_DATE 已经 returns STRING

自动转换日期以格式化 YYWW

Automatizing conversion dates to format YYWW

google-bigquery

bigquery-standard-sql