UNNEST(hit.eCommerceAction)，谷歌Bigquery

Question

我使用了相同的逻辑来取消hit.eCommerceAction的嵌套，但它不像其他字段那样工作。对这个问题有什么帮助吗？另外，max(if())函数是用来获取两个hits.customeDimenison.value的正确函数吗？

SELECT
 Date
  ,COUNT(DISTINCT FULLVISITORID)
 , product.v2ProductCategory

  ,max(if(customDimensions.index=2, customDimensions.value,null))  as dest
  ,max(if(customDimensions.index=21, customDimensions.value,null))  as pax
 ,eCommerceAction.action_type
 ,product.v2ProductName

FROM `table` as t
  CROSS JOIN UNNEST(hits) AS hit
  CROSS JOIN UNNEST(hit.customDimensions) AS customDimensions
  CROSS JOIN UNNEST(hit.eCommerceAction) as eCommerceAction
  CROSS JOIN UNNEST(hit.product) AS product
GROUP BY 
      Date
      ,product.v2ProductCategory
    ,eCommerceAction.action_type
,product.v2ProductName

我得到的错误代码是Error: UNNEST中引用的值必须是数组。UNNEST包含类型为STRUCT的表达式

Answer 1

我可以用一个更简单的查询重现这个错误：

#standardSQL
SELECT DISTINCT hit.eCommerceAction.action_type 
FROM `73156703.ga_sessions_20170109` t
  , UNNEST(hits) hit
  , UNNEST(hit.customDimensions) customDimensions
  , UNNEST(hit.eCommerceAction) as eCommerceAction

这里的问题是eCommerceAction不是REPEATED记录，因此没有UNNEST的数组。

固定查询：

#standardSQL
SELECT DISTINCT hit.eCommerceAction.action_type 
FROM `ga_sessions_20170109`  t
  , UNNEST(hits) hit
  , UNNEST(hit.customDimensions) customDimensions