r语言 - 无法使用谷歌大查询(标准)取消嵌套某些字段

Question

我有一个嵌套表，我无法使用标准谷歌大查询访问所有字段。

例如，此查询失败

SELECT  *
FROM 
    (
    SELECT
           rev_info.user.id as player_id,
           rev_info.purchase.total.currency as currency,
           rev_info.purchase.total.amount as REV
          ,rev_info.purchase.virtual_items.items.sku     as sku 
    FROM `gcs.rev`
    )
WHERE currency = 'USD'

有错误

"错误：无法访问 ARRAY 类型的值的字段 SKU>在 [9：59]"

然而

SELECT  *
FROM 
    (
    SELECT
           rev_info.user.id as player_id,
           rev_info.purchase.total.currency as currency,
           rev_info.purchase.total.amount as REV
          --,rev_info.purchase.virtual_items.items.sku   as sku 
    FROM `gcs.rev`
    )
WHERE currency = 'USD'

此查询很好。

另请注意

SELECT
       rev_info.purchase.virtual_items.items.sku     as sku 
FROM `gcs.rev`

失败，出现与上述相同的错误。

Answer 1

扩展 Elliott 的答案 - 我认为在这里您首先需要取消嵌套，但随后您很可能需要聚合回您的sku。 否则你会得到相当多余（扁平化）的输出

我觉得下面是您可能需要的 - 它适用于 BigQuery Standard SQL

#standardSQL
SELECT 
  player_id, 
  currency, 
  REV, 
  STRING_AGG(sku) SKUs
FROM (
  SELECT
    rev_info.user.id AS player_id,
    rev_info.purchase.total.currency AS currency,
    rev_info.purchase.total.amount AS REV,
    item.sku AS sku 
  FROM `gcs.rev` t,
  UNNEST(t.rev_info.purchase.virtual_items.items) item
)
WHERE currency = 'USD'
GROUP BY 1, 2, 3   

因此，所有 SKU 都将显示为给定player_id的列表，以及金额和货币

根据艾略特的评论/建议添加

#standardSQL
SELECT
  rev_info.user.id AS player_id,
  rev_info.purchase.total.currency AS currency,
  rev_info.purchase.total.amount AS REV,
  (SELECT STRING_AGG(item.sku) 
     FROM UNNEST(t.rev_info.purchase.virtual_items.items) item
  ) AS SKUs 
FROM `gcs.rev` t,
WHERE currency = 'USD'

Answer 2

如果您的目标是为每个items数组元素获取一行，则可以在表和rev_info.purchase.virtual_items.items之间使用逗号（join）运算符。例如

SELECT *
FROM (
  SELECT
    rev_info.user.id as player_id,
    rev_info.purchase.total.currency as currency,
    rev_info.purchase.total.amount as REV,
    item.sku as sku 
  FROM `gcs.rev` t,
    t.rev_info.purchase.virtual_items.items item
)
WHERE currency = 'USD'