Calculating the diference from a value to a previous row in function of an id and date

[Anonymous]

Dear Team,

I would like to be able to calculate the following difference column, it seems that it's a hard nut to crack.

ID	DATE	READING	Difference
A	1/10/2019	23	13
A	30/09/2019	10	5
A	26/09/2019	5	0
B	5/08/2019	50	24
B	3/08/2019	26	6
B	2/06/2019	20	20
C	1/09/2019	67	27
C	6/08/2019	40	17
C	1/01/2019	23	23

Everything is very welcome,

Greatly appreciated

[v-diye-msft]

Hi @Anonymous 

Sorry, I don't understand the calculation logic, could you please specify more? Does the difference column is the expected results? how does it count? 

If you'd like to count the difference in adjacent rows, the output seems incorrect.

 23-10=13

10-5=5

5-50=0????

50-26=24

26-20=6

20-67=20???

67-40=27

40-23=17

23-0=23

[Anonymous]

Dear @Anonymous 

You can create a column which calculates the previous READING using date/period and calculate the difference between those two columns.

Regards, 

Munna 

[Anonymous]

You can use the following link for the details

https://community.powerbi.com/t5/Desktop/Calculate-Difference-from-Previous-Date-Dynamically/td-p/34...