扩大日期范围时，数组索引 1 超出范围（溢出）

Question

我正在运行以下查询来返回每个用户最常购买的类别，这在 30 天和 60 天的日期范围内运行良好，但是当我尝试在过去 100 天运行它时，我收到错误：

Array index 1 is out of bounds (overflow)

为什么扩大日期范围会导致此错误？

WITH `query_result` AS (

SELECT customDimension.value AS UserID,
SUM(CASE WHEN LOWER(hits_product.v2ProductName) LIKE "% mens%" THEN 1 ELSE 0 END) AS mens,
SUM(CASE WHEN LOWER(hits_product.v2ProductName) LIKE "%womens%" THEN 1 ELSE 0 END) AS womens,
SUM(CASE WHEN LOWER(hits_product.v2ProductName) LIKE "%boys%" 
OR LOWER(hits_product.v2ProductName) LIKE "%girls%"
THEN 1 ELSE 0 END) AS kids
FROM `xxx.xxx.ga_sessions_20*` AS t
  CROSS JOIN UNNEST(hits) AS hits
  CROSS JOIN UNNEST(t.customdimensions) AS customDimension
  CROSS JOIN UNNEST(hits.product) AS hits_product
WHERE parse_date('%y%m%d', _table_suffix) between 
DATE_sub(current_date(), interval 100 day) and
DATE_sub(current_date(), interval 1 day)
AND customDimension.index = 2
AND hits.eCommerceAction.action_type = "6"
GROUP BY UserID
HAVING
SUM(CASE WHEN LOWER(hits_product.v2ProductName) LIKE "%boys%" 
OR LOWER(hits_product.v2ProductName) LIKE "%girls%"
THEN 1 ELSE 0 END) > 0
)
  SELECT *, 
  ARRAY_TO_STRING(ARRAY(
    SELECT SPLIT(kv, ':')[OFFSET(0)]
    FROM UNNEST(SPLIT(REGEXP_REPLACE(TO_JSON_STRING(t), r'[{"}]', ''))) kv
    WHERE LOWER(SPLIT(kv, ':')[OFFSET(0)]) <> LOWER('UserID')
    ORDER BY CAST(SPLIT(kv, ':')[OFFSET(1)] AS INT64) DESC
    LIMIT 1
  ), ',') top_purchased_gender
FROM `query_result` t

Answer 1

只需使用[safe_offset (1)]而不是[offset (1)]处理 null 异常

像这样：

ORDER BY CAST(ifnull(SPLIT(kv, ':')[safe_offset (1)], 0) AS INT64) DESC

https://cloud.google.com/bigquery/docs/reference/standard-sql/operators#array_subscript_operator

https://cloud.google.com/bigquery/docs/reference/standard-sql/conditional_expressions#ifnull