BigQuery无效的字段名称_PARTITIONDATE或_PARTITIONTIME

Question

在日期分区表中，您应该可以运行：

    SELECT
      _PARTITIONDATE,
      COUNT(*)
    FROM table
    GROUP BY 1
    ORDER BY 1

但是，运行此命令将返回错误：

Invalid field name "_PARTITIONDATE". Field names are not allowed to start with the (case-insensitive) prefixes _PARTITION, _TABLE_, _FILE_ and _ROW_TIMESTAMP

为什么不起作用？

Answer 1

事实证明，您所需要做的就是重命名查询中的_PARTITIONDATE或_PARTITIONTIME字段：

SELECT 
    -- _PARTITIONDATE alone will not work
    _PARTITIONDATE as partition_date,
    COUNT(*)
FROM table
GROUP BY 1
ORDER BY 1