Question

此查询每月失败一次，因为BETWEEN部分无效。在value BETWEEN min AND max的位置，3月1日我的查询将再次失败，因为它将计算到partition_2 BETWEEN 28 AND 1。如何使此查询更可靠，但仍然只使用所需的分区？

WITH recent_tasks AS
(SELECT task_id, state, timestamp, partition_0, partition_1, partition_2,
  row_number() OVER (PARTITION BY task_id
               ORDER BY timestamp DESC) AS rn
FROM firehose
WHERE
 "partition_0" BETWEEN to_char(current_date - interval '1' day, 'yyyy') AND to_char(current_date, 'yyyy')
 and "partition_1" BETWEEN to_char(current_date - interval '1' day, 'mm') AND to_char(current_date, 'mm')
 and "partition_2" BETWEEN to_char(current_date - interval '1' day, 'dd') AND to_char(current_date, 'dd')
ORDER BY rn)
SELECT * FROM recent_tasks
WHERE rn=1

一对夫妇注意到：

分区是char值而不是整数
partition_2是月份分区
查询的目的是查找每个task_id的最新状态
使用AWS Athena
数据以S3 / yyyy / mm / dd格式存储，每天都是新分区

理想情况下，我的查询会正确处理每月转换：

BETWEEN FEB 10 AND FEB 11 (works with above)
BETWEEN FEB 28 AND MAR 1  (fails with above)
BETWEEN MAR 1 AND MAR 2   (works with above)

Answer 1

如果你想要达到零而不是28：

cast(to_char(current_date, 'dd') as signed)-1

所以，在03/01，这将返回1 - to_char（current_date，＆＃39; dd＆＃39;），然后减去它会给你一个零：

and "partition_2" BETWEEN to_char(cast(to_char(current_date, 'dd') as signed)-1) AND to_char(current_date, 'dd')

此查询每月失败一次，如何重构？

1 个答案: