问题
I have a query that I don't really know how to begin with. I'm hoping someone can help me out with it. I will start by explaining the table
I have a device table with four columns: Device_Id, Device_Status, Begin_dt, End_dt there are 6 different statuses where 3 (for simplicity lets say status 1, 4 and 5) mean the device is 'online'
an example of this table could be
Id | Status| Begin | End
001| 1 | 2012-09-01 00:00:00.000 | 2012-09-01 01:00:00.000
001| 2 | 2012-09-01 01:00:00.000 | 2012-09-01 01:35:00.000
001| 1 | 2012-09-01 01:35:00.000 | 2012-09-01 02:05:00.000
003| 1 | 2012-09-01 05:00:00.000 | 2012-09-01 07:02:00.000
004| 1 | 2012-09-01 01:00:00.000 | 2012-09-01 01:35:00.000
003| 2 | 2012-09-01 07:02:00.000 | NULL
My query needs to return the Sum of the TIME all the devices have a status that indicates 'online' for each hour in a 24 hour period.
so my return should look like
Hour| Online_Time
0 | 5:30:12.11
1 | 3:30:12.11
2 | 4:30:12.11
3 | 5:30:12.11
4 | 6:30:12.11
5 | 4:00:00.00
6 | 1:30:12.11
7 | 3:30:12.11
8 | 4:30:12.11
etc |
So for each hour of the day I can have more than 1 hour of online time (obviously) because for example if I have 5 devices all online for the whole hour I would have 5 hours of online time for that hour.
This is kind of complex and I hope I did a good job of explaining it, anyone that can help or give a suggestion is greatly appreciated.
-J
with const as (
select dateadd(hour, 1, cast(cast(getdate() -1 as date) as datetime)) as midnnight
),
allhours as (
select 0 as hour, midnight as timestart, dateadd(hour, 1, timestart) as timeend from const union all
select 1 as hour, dateadd(hour, 1, midnight), dateadd(hour, 2, midnight) from const union all
select 2 as hour, dateadd(hour, 2, midnight), dateadd(hour, 3, midnight) from const union all
select 3 as hour, dateadd(hour, 3, midnight), dateadd(hour, 4, midnight) from const union all
select 4 as hour, dateadd(hour, 4, midnight), dateadd(hour, 5, midnight) from const union all
select 5 as hour, dateadd(hour, 5, midnight), dateadd(hour, 6, midnight) from const union all
select 6 as hour, dateadd(hour, 6, midnight), dateadd(hour, 7, midnight) from const union all
select 7 as hour, dateadd(hour, 7, midnight), dateadd(hour, 8, midnight) from const union all
select 8 as hour, dateadd(hour, 8, midnight), dateadd(hour, 9, midnight) from const union all
select 9 as hour, dateadd(hour, 9, midnight), dateadd(hour, 10, midnight) from const union all
select 10 as hour, dateadd(hour, 10, midnight), dateadd(hour, 11, midnight) from const union all
select 11 as hour, dateadd(hour, 11, midnight), dateadd(hour, 12, midnight) from const union all
select 12 as hour, dateadd(hour, 12, midnight), dateadd(hour, 13, midnight) from const union all
select 13 as hour, dateadd(hour, 13, midnight), dateadd(hour, 14, midnight) from const union all
select 14 as hour, dateadd(hour, 14, midnight), dateadd(hour, 15, midnight) from const union all
select 15 as hour, dateadd(hour, 15, midnight), dateadd(hour, 16, midnight) from const union all
select 16 as hour, dateadd(hour, 16, midnight), dateadd(hour, 17, midnight) from const union all
select 17 as hour, dateadd(hour, 17, midnight), dateadd(hour, 18, midnight) from const union all
select 18 as hour, dateadd(hour, 18, midnight), dateadd(hour, 19, midnight) from const union all
select 19 as hour, dateadd(hour, 19, midnight), dateadd(hour, 20, midnight) from const union all
select 20 as hour, dateadd(hour, 20, midnight), dateadd(hour, 21, midnight) from const union all
select 21 as hour, dateadd(hour, 21, midnight), dateadd(hour, 22, midnight) from const union all
select 22 as hour, dateadd(hour, 22, midnight), dateadd(hour, 23, midnight) from const union all
select 23 as hour, dateadd(hour, 23, midnight), dateadd(hour, 24, midnight) from const union all
)
select ah.hour,
sum(datediff(ms, (case when ah.timestart >= dt.Begin_Dt then timestart else dt.Begin_Dt end),
(case when ah.timeend <= dt.End_Dt then ah.timeend else dt.End_Dt end))) as totalms,
cast(dateadd(ms, sum(datediff(ms, (case when ah.timestart >= dt.Begin_Dt then timestart else dt.Begin_Dt end),
(case when ah.timeend <= dt.End_Dt then ah.timeend else dt.End_Dt end))),0) as time
) as totalTime
from allhours as ah left outer join
dataTable as dt
on ah.timestart< coalesce(dt.End_dt, getdate()) and
ah.timeend >= dt.Begin_Dt
group by ah.hour
order by ah.hour
This is what I have right now, I'm getting an error on the ')'
select 23 as hour, dateadd(hour, 23, midnight), dateadd(hour, 24, midnight) from const union all
) <----- Incorrect syntax near ')'. Expecting SELECT, or '('.
select ah.hour,
回答1:
Your problem seems to be that the time span needs to be broken up in hours. So, you need to start with all hours in the day. Then you calculate the overlap, sum up the differences (below in milliseconds) and convert everything back to a time for the output.
with const as (
select dateadd(hour, 1, cast(cast(getdate() -1 as date) as datetime)) as midnight
),
allhours as (
select 0 as hour, midnight as timestart, dateadd(hour, 1, midnight) as timeend from const union all
select 1 as hour, dateadd(hour, 1, midnight), dateadd(hour, 2, midnight) from const union all
select 2 as hour, dateadd(hour, 2, midnight), dateadd(hour, 3, midnight) from const union all
. . .
select 23 as hour, dateadd(hour, 23, midnight), dateadd(hour, 24, midnight) from const
)
select ah.hour,
sum(datediff(ms, (case when ah.timestart >= dt.begin then timestart else dt.begin end),
(case when ah.timeend <= dt.end then ah.timeend else dt.end end)
)
) as totalms,
cast(dateadd(ms, sum(datediff(ms, (case when ah.timestart >= dt.begin then timestart else dt.begin end),
(case when ah.timeend <= dt.end then ah.timeend else dt.end end)
)
),
0) as time
) as totalTime
from allhours ah left outer join
DeviceTable dt
on ah.timestart< coalesce(dt.end, getdate()) and
ah.timeend >= dt.begin
group by ah.hour
order by ah.hour
Also, to make this work, you need to wrap "begin" and "end" in double quotes or square brackets. These are reserved words in T-SQL. And you need to replace the ". . ." with additional lines for hours from 3 to 22.
回答2:
Something like this might get you started.
select SUM(datediff(second, Begin_dt, End_dt)) as seconds_online
,DATEPART(hour, Begin_dt) as [hour]
from table
where device_status in (1,4,5)
group by DATEPART(hour, Begin_dt)
To format the result you may want to follow this question:
SQL - Seconds to Day, Hour, Minute, Second
来源：https://stackoverflow.com/questions/12387873/tsql-query-returns-values-for-each-hour-for-the-past-24-hours