复制记录组以填补 Google BigQuery 中的多个日期空白

Posted 2023-03-24

【中文标题】复制记录组以填补 Google BigQuery 中的多个日期空白

【英文标题】：Duplicate groups of records to fill multiple date gaps in Google BigQuery

【发布时间】：2017-02-07 18:57:56

【问题描述】：

我发现了一个类似的问题 (Duplicating records to fill gap between dates in Google BigQuery)，但是在不同的情况下，那里的答案不适用。

我有这样的数据结构（基本上是多个产品和合作伙伴的价格变化历史）：

+------------+---------+---------+-------+
|    date    | product | partner | value |
+------------+---------+---------+-------+
| 2017-01-01 | a       | x       |    10 |
| 2017-01-01 | b       | x       |    15 |
| 2017-01-01 | a       | y       |    11 |
| 2017-01-01 | b       | y       |    16 |
| 2017-01-05 | b       | x       |    13 |
| 2017-01-07 | a       | y       |    15 |
| 2017-01-07 | a       | x       |    15 |
+------------+---------+---------+-------+

我需要的是一个查询（专门用 BigQuery 标准 SQL 编写），给定一个日期范围（在本例中为 2017-01-01 到 2017-01-10），输出以下结果：

+--------------+---------+---------+-------+
|      date    | product | partner | value |
+--------------+---------+---------+-------+
|   2017-01-01 | a       | x       |    10 |
|   2017-01-02 | a       | x       |    10 |
|   2017-01-03 | a       | x       |    10 |
|   2017-01-04 | a       | x       |    10 |
|   2017-01-05 | a       | x       |    10 |
|   2017-01-06 | a       | x       |    10 |
|   2017-01-07 | a       | x       |    15 |
|   2017-01-08 | a       | x       |    15 |
|   2017-01-09 | a       | x       |    15 |
|   2017-01-10 | a       | x       |    15 |
|   2017-01-01 | a       | y       |    11 |
|   2017-01-02 | a       | y       |    11 |
|   2017-01-03 | a       | y       |    11 |
|   2017-01-04 | a       | y       |    11 |
|   2017-01-05 | a       | y       |    11 |
|   2017-01-06 | a       | y       |    11 |
|   2017-01-07 | a       | y       |    15 |
|   2017-01-08 | a       | y       |    15 |
|   2017-01-09 | a       | y       |    15 |
|   2017-01-10 | a       | y       |    15 |
|   2017-01-01 | b       | x       |    15 |
|   2017-01-02 | b       | x       |    15 |
|   2017-01-03 | b       | x       |    15 |
|   2017-01-04 | b       | x       |    15 |
|   2017-01-05 | b       | x       |    13 |
|   2017-01-06 | b       | x       |    13 |
|   2017-01-07 | b       | x       |    13 |
|   2017-01-08 | b       | x       |    13 |
|   2017-01-09 | b       | x       |    13 |
|   2017-01-10 | b       | x       |    13 |
|   2017-01-01 | b       | y       |    16 |
|   2017-01-02 | b       | y       |    16 |
|   2017-01-03 | b       | y       |    16 |
|   2017-01-04 | b       | y       |    16 |
|   2017-01-05 | b       | y       |    16 |
|   2017-01-06 | b       | y       |    16 |
|   2017-01-07 | b       | y       |    16 |
|   2017-01-08 | b       | y       |    16 |
|   2017-01-09 | b       | y       |    16 |
|   2017-01-10 | b       | y       |    16 |
+--------------+---------+---------+-------+

对于产品和合作伙伴的每种组合，基本上都是一个价格历史记录，其中包含所有日期空白。

我很难弄清楚如何完成这项工作，尤其是如何在没有发生价格变化的同一日期生成多行。有什么想法吗？

【问题讨论】：

到目前为止您尝试过什么？从您的问题中，我不明白您将如何在每个日期得到多行。是什么决定的？

@ElliottBrossard 前提是我需要每天重复产品和合作伙伴的每个组合的最新值，并且它们的值没有改变。因此，如果我有两个产品和两个合作伙伴，那么在没有值变化的日子里应该有 4 行具有最新值

【参考方案1】：

下面试试

#standardSQL
WITH history AS (
  SELECT '2017-01-01' AS d, 'a' AS product, 'x' AS partner, 10 AS value UNION ALL
  SELECT '2017-01-01' AS d, 'b' AS product, 'x' AS partner, 15 AS value UNION ALL
  SELECT '2017-01-01' AS d, 'a' AS product, 'y' AS partner, 11 AS value UNION ALL
  SELECT '2017-01-01' AS d, 'b' AS product, 'y' AS partner, 16 AS value UNION ALL
  SELECT '2017-01-05' AS d, 'b' AS product, 'x' AS partner, 13 AS value UNION ALL
  SELECT '2017-01-07' AS d, 'a' AS product, 'y' AS partner, 15 AS value UNION ALL
  SELECT '2017-01-07' AS d, 'a' AS product, 'x' AS partner, 15 AS value 
),
daterange AS (
  SELECT date_in_range  
  FROM UNNEST(GENERATE_DATE_ARRAY('2017-01-01', '2017-01-10')) AS date_in_range 
),
temp AS (
  SELECT d, product, partner, value, LEAD(d) OVER(PARTITION BY product, partner ORDER BY d) AS next_d
  FROM history
  ORDER BY product, partner, d
)
SELECT date_in_range, product, partner, value
FROM daterange
JOIN temp
ON daterange.date_in_range >= PARSE_DATE('%Y-%m-%d', temp.d) 
AND (daterange.date_in_range < PARSE_DATE('%Y-%m-%d', temp.next_d) OR temp.next_d IS NULL)
ORDER BY product, partner, date_in_range