Question

我想从另一个查询中获得的结果查询每分钟的总和，该查询计算后续值之间的差异。

Select * 
from 
  (
    (select division.name,
            date(meter_data.reading_date) AS reading_date,
            sum(meter_data.meter_delta) 'Gas Consumption (m3)'
     from meter, meter_data, division
     where meter.meter_id = meter_data.meter_id 
       and meter.division_id = division.division_id
       and Date(meter_data.reading_date) between '2018-04-01' and '2018-05-03' 
     group by date(meter_data.reading_date) 
    ) as table1,

    (Select Date(receipt.receipt_date) AS receipt_date, 
            sum(case receipt_item.item_name 
                    when 'Gas' then receipt_item.item_amount else 0 
                end) 'Gas Purchase'
     from receipt_item, receipt
     where receipt.receipt_id = receipt_item.receipt_id
       and Date(receipt.receipt_date) between '2018-04-01' and '2018-05-03'  
     group by Date(receipt.receipt_date)
    ) as table2
  )
WHERE table1.reading_date = table2.receipt_date;

例如，如果我从suqbquery

获得以下内容

select sum(ph1), sum(ph2), sum(ph2) from (select 
non_negative_difference(day_chan1) as ph1,
non_negative_difference(day_chan2) as ph2, 
non_negative_difference(day_chan3) as ph3 
from electricity) 
group by time(1m) tz('Europe/Dublin')

我想将它们总结为

time                 ph1 ph2 ph3
----                 --- --- ---
2017-04-02T14:40:38Z 0   0   2
2017-04-02T14:41:38Z 1   1   1
2017-04-02T14:41:39Z 0   0   2
2017-04-02T14:42:38Z 1   1   1
2017-04-02T14:42:39Z 0   1   2

但我从查询得到的是time ph1 ph2 ph3 ---- --- --- --- 2017-04-02T14:40:00Z 0 0 2 2017-04-02T14:41:00Z 1 1 3 2017-04-02T14:42:00Z 1 2 3，但是如果我自己做了子查询，它会返回结果

Answer 1

我也为此花了很长时间，终于找到了解决方案：

select sum(ph1), sum(ph2), sum(ph2) from (select

这是正确的。现在我们要在non_negative_difference调用中添加一个聚合函数（正如错误也表明的那样）。我想你想总结一切。

non_negative_difference(sum(day_chan1)) as ph1,
non_negative_difference(sum(day_chan2)) as ph2, 
non_negative_difference(sum(day_chan3)) as ph3 
from electricity

现在，如果不添加以下行，则内部查询的按功能分组也将为1m。我们不希望这样，因为如果缺少值，则潮涌计算总和的方式将导致很大的差异。因此，我们按照您拥有的最小间隔（例如1秒）对该子查询进行分组

group by time(1s))

最后，您可以按照希望将值加在一起的间隔对外部查询进行分组。

group by time(1m) tz('Europe/Dublin')

Influxdb - 如何计算每分钟的差异总和

1 个答案: