无法识别的名称：在 BigQuery 中使用 UNNEST WHERE 时

Posted 2023-03-24

【中文标题】无法识别的名称：在 BigQuery 中使用 UNNEST WHERE 时

【英文标题】：Unrecognised name: when using UNNEST WHERE in BigQuery

【发布时间】：2021-02-26 17:49:54

【问题描述】：

我正在尝试在 BigQuery 中按照 this blog 进行过滤，但我无法使该模式正常工作。

博客中的可重现示例效果非常好。

SELECT event_name, event_timestamp, user_pseudo_id, 
  event_params
FROM `firebase-public-project.analytics_153293282.events_20181003`
WHERE event_name = "level_complete_quickplay"

SELECT event_name, event_timestamp, user_pseudo_id, 
  (SELECT value.int_value FROM UNNEST(event_params) 
    WHERE key = "value") AS score
FROM `firebase-public-project.analytics_153293282.events_20181003`
WHERE event_name = "level_complete_quickplay"

当我在自己的桌子上尝试此操作时，我收到错误 Unrecognised name:。我试图在玩具桌nested_seq 中重现错误。

WITH sequences AS (
  SELECT 
    [0, 1, 1, 2, 3, 5] AS some_numbers
    UNION ALL SELECT [2, 4, 8, 16, 32] AS some_numbers
    UNION ALL SELECT [5, 10] AS some_numbers
), 
-- table containing repeated record
nested_seq AS (
  SELECT 
    some_numbers,
    some_numbers[OFFSET(1)] AS offset_1,
    some_numbers[ORDINAL(1)] AS ordinal_1
  FROM sequences
)
-- transformation to extract single value from array
SELECT *
FROM nested_seq
LEFT JOIN (SELECT 
  some_numbers
  FROM UNNEST(some_numbers)
  WHERE some_numbers = 2)
-- Unrecognized name: some_numbers at [21:19] 

我期望some_numbers 的元素可以被提取，这样我就可以在不增加行数的情况下取消嵌套数组。

Row	some_numbers	offset_1	ordinal_1
1	2	1	0
2	2	4	2
3	null	10	5

【参考方案1】：

... some_numbers 的元素可以被提取出来，这样我就可以在不增加行数的情况下取消嵌套数组。

考虑下面的“修复”

WITH sequences AS (
  SELECT 
    [0, 1, 1, 2, 3, 5] AS some_numbers
    UNION ALL SELECT [2, 4, 8, 16, 32] AS some_numbers
    UNION ALL SELECT [5, 10] AS some_numbers
)
SELECT # some_numbers,
  (SELECT some_number
    FROM t.some_numbers some_number
    WHERE some_number = 2
  ) some_number,
  some_numbers[OFFSET(1)] AS offset_1,
  some_numbers[ORDINAL(1)] AS ordinal_1
FROM sequences t

有输出