Impala-在多个日期上运行相同的查询

Question

我有下面的Impala查询，该查询被设置为对数据集中的设备数量进行计数，而不是前一天。我想在多个日期（过去一年的每一天）中运行此查询。

在Impala中有什么方法可以做到这一点？我知道没有循环功能，但是不确定是否有某种方法可以将日期数组传递给变量，以便查询可以在连续的日期上运行。谢谢！

SELECT COUNT(DISTINCT devices) 
FROM request
WHERE devices NOT IN (
    SELECT devices
    FROM request
    WHERE forwarded_dt =  CAST((CAST('2020-03-17' as timestamp)) as BIGINT)*1000
    )  
AND forwarded_dt =  CAST((CAST('2020-03-18' as timestamp)) as BIGINT)*1000;

Answer 1

您可以使用lag()。我认为：

select day,
       count(*) as num_devices_on_day,
       sum(case when prev_day = day - interval '1' day then 0 else 1 end) as new_devices_on_day
from (select device, date_trunc('day', timestamp) as day,
             lag(date_trunc('day', timestamp)) over (order by min(timestamp)) as prev_day
      from requests
     ) r
group by day;