Question

我有两个具有相似数据的查询（一个具有前一个周期，另一个具有当前周期）。我需要在剑道折线图中显示它。我怎么能这样做**

select date_trunc('hour' , "CreateDateTime"::TIMESTAMP) as c, 
       count(1) as d 
from "ROBOT" 
where "CreateDateTime"::TIMESTAMP between '2018-04-01' and '2018-04-22' 
group by date_trunc('hour', "CreateDateTime"::TIMESTAMP) 

UNION ALL

select date_trunc('hour' , "CreateDateTime"::TIMESTAMP) as a, 
count(1) as b 
from "ROBOT" 
where "CreateDateTime"::TIMESTAMP between '2018-05-01' and '2018-05-22' 
group by date_trunc('hour', "CreateDateTime"::TIMESTAMP);

Answer 1

看起来你想要两个月的小时计数。假设这是正确的，你想要像：

select date_part('hour', "CreateDateTime"::TIMESTAMP) as hour,
       sum(case when "CreateDateTime"::TIMESTAMP between '2018-04-01' and '2018-04-22' then 1 else 0 end) as apr,
       sum(case when "CreateDateTime"::TIMESTAMP between '2018-05-01' and '2018-05-22' then 1 else 0 end) as may
from "ROBOT"
where "CreateDateTime"::TIMESTAMP between '2018-04-01' and '2018-04-22'
   or "CreateDateTime"::TIMESTAMP between '2018-05-01' and '2018-05-22'
group by 1;

当您想要使用不同标准从相同数据生成多个总和时，sum（case ...）模式是一个很好的模式。

postgres中的时间戳比较

1 个答案: