Interval aggregation of 5 minutes for last 24 hours in database - sql-server

Question

I am trying to aggregate the data for last 24 hours on 5 min interval basis. I had written following query:
select
DATEADD(MINUTE, DATEDIFF(MINUTE, '2000', t.datetime) / 5 * 5, '2000')
as datetimevalue,
cast(sum(t.value) as decimal(10,2)) as value
from
dbo.data t
where
t.datetime <= '2020-09-12 19:23:00.000'
and t.datetime > DATEADD(day,-1,'2020-09-12 19:23:00.000')
group by
DATEADD(MINUTE, DATEDIFF(MINUTE, '2000', t.datetime) / 5 * 5, '2000')
order by
datetimevalue asc
The result is returned like this:
datetimevalue value
------------------------------------
2020-09-12 18:45:00.000, 54227.16
2020-09-12 18:50:00.000, 53681.54
2020-09-12 18:55:00.000, 49379.01
2020-09-12 19:00:00.000, 50751.53
2020-09-12 19:05:00.000, 55033.14
2020-09-12 19:10:00.000, 55858.37
2020-09-12 19:15:00.000, 54236.57
2020-09-12 19:20:00.000, 26731.36
I need aggregation of last 5 minute starting from current timestamp insteead of above which is aggregating last 3 minutes and then 5 minutes after that.
For example
datetimevalue value
--------------------------------------
2020-09-12 19:03:00.000, 22444.47
2020-09-12 19:08:00.000, 45674.46
2020-09-12 19:13:00.000, 35737.23
2020-09-12 19:18:00.000, 34675.34
Any assistance appreciated.

Answer 1

You need to calculate the offset to the aggregation time window (5 minutes), substract it while calculating values and the add it again to the final times:
DECLARE #dt DATETIME = GETDATE()
DECLARE #offset INT = (DATEDIFF(SECOND, CAST(CAST(#dt AS DATE) AS DATETIME), #dt) % (60 * 5)) / 60 * 60
-- In case you want an offset in seconds
--DECLARE #diff INT = DATEDIFF(SECOND, CAST(CAST(#dt AS DATE) AS DATETIME), #dt) % (60 * 5)
SELECT DATEADD(SECOND, #offset, datetimevalue) AS datetimevalue, value
FROM (
SELECT
DATEADD(MINUTE, DATEDIFF(MINUTE, '2000', DATEADD(SECOND, -#offset, t.DATETIME)) / 5 * 5, '2000') AS datetimevalue
,cast(sum(t.value) AS DECIMAL(10, 2)) AS value
FROM dbo.data t
WHERE t.DATETIME <= #dt
-- in case you want only for last 24 hours
-- AND t.DATETIME > DATEADD(DAY, - 1, #dt)
-- in case if you want to include offset in last timestamp
AND t.DATETIME > DATEADD(SECOND, -#offset, DATEADD(DAY, - 1, #dt))
GROUP BY DATEADD(MINUTE, DATEDIFF(MINUTE, '2000', DATEADD(SECOND, -#offset, t.DATETIME)) / 5 * 5, '2000')
) T
ORDER BY datetimevalue DESC