How to subtract values between two particular dates in Powerbi? - powerbi

Question

I have a table like this:
DeviceID
SignalID
Value
DateTime
1
22
1032223
01.10.2022 00:00:00
2
24
1923892
01.10.2022 00:00:00
3
33
3434342
01.10.2022 00:00:00
4
33
3232323
01.10.2022 00:00:00
.......
......
......
......
1
33
4155151
05.12.2022 15:36:38
I have a few devices with each device monitoring signals. The signal value here represents some counter value. The counter are running continously but I need their relative value as in from 01.10.2022.
What I want to calculate :
The value of the signalID x of device y = (value now) - (value on 01.10.2022 00:00:00).
How can I acheive this for all the value of the signalID of all the devices?

Answer 1

You can test this, and let me know if It solves your problem!
15Seconds_Cardinality =
VAR NowTime =
NOW ()
VAR FixedTime =
DATE ( 2022, 10, 01 ) + TIME ( 0, 0, 0 )
VAR Value_On_FixedDate =
CALCULATE (
MIN ( Signals[Value] ),
YEAR ( Signals[DateTime] ) = YEAR ( FixedTime ),
MONTH ( Signals[DateTime] ) = MONTH ( FixedTime ),
DAY ( Signals[DateTime] ) = DAY ( FixedTime ),
HOUR ( Signals[DateTime] ) = HOUR ( FixedTime ),
MINUTE ( Signals[DateTime] ) = MINUTE ( FixedTime ),
ROUND ( SECOND ( Signals[DateTime] ) / 15, 0 )
= ROUND ( SECOND ( FixedTime ) / 15, 0 )
)
VAR Value_On_Now =
CALCULATE (
MAX ( Signals[Value] ),
YEAR ( Signals[DateTime] ) = YEAR ( NowTime ),
MONTH ( Signals[DateTime] ) = MONTH ( NowTime ),
DAY ( Signals[DateTime] ) = DAY ( NowTime ),
HOUR ( Signals[DateTime] ) = HOUR ( NowTime ),
MINUTE ( Signals[DateTime] ) = MINUTE ( NowTime ),
ROUND ( SECOND ( Signals[DateTime] ) / 15, 0 )
= ROUND ( SECOND ( NowTime ) / 15, 0 )
)
RETURN
Value_On_Now - Value_On_FixedDate
Same above code with image file: