sql - 尝试使用 BigQuery 选择事件数据时出错

Question

我尝试在 BigQuery 中选择 event_dim.date，但由于错误而无法实际访问它

Error: Cannot access field date on a value with type ARRAY<STRUCT<date STRING, name STRING, params ARRAY<STRUCT<key STRING, value STRUCT<string_value STRING, int_value INT64, float_value FLOAT, ...>>>, ...>> at [1:18]

我的查询:

SELECT event_dim.date FROM `table`

我知道我做错了，任何帮助将不胜感激。谢谢!

Answer 1

您是否想获取每行的日期数组？然后你需要一个 ARRAY 子查询:

SELECT ARRAY(SELECT date FROM UNNEST(event_dim)) AS dates
FROM `table`;

如果您尝试获取单独行中的所有日期，那么您需要与数组交叉连接:

SELECT event.date
FROM `table`
CROSS JOIN UNNEST(event_dim) AS event;

要过滤特定日期:

SELECT event.date
FROM `table`
CROSS JOIN UNNEST(event_dim) AS event
WHERE event.date = '20170104';

或者您可以将日期字符串解析为 date 类型，这样您就可以按年或周进行过滤，例如:

SELECT date
FROM (
  SELECT PARSE_DATE('%Y%m%d', event.date) AS date
  FROM `table`
  CROSS JOIN UNNEST(event_dim) AS event
)
WHERE EXTRACT(YEAR FROM date) = 2017;