Difference between values in the same column for unique index

[Karlie69]

Hi 🙂

I am having trouble calculating the difference between values in the same column.

My dataset is like this:

I added a matrix table based on this data to the dasboard that looks like this:

Now I would like to add a column to this table that would calculate the Avr. currency price difference between 2021 and 2020 for each unique Part_no. There are blanks in the data. Unfortunately, I do not know how to write the DAX formula

Anyone know the answer? 🙂

[Anonymous · Accepted solution]

Hi @Karlie69 ,

difff = 
var _pre=CALCULATE(SUM('Table'[Avr]),FILTER('Table',[Part_no]=EARLIER('Table'[Part_no]) && [Year]=EARLIER([Year])-1))
return  IF(_pre=BLANK(),BLANK(), [Avr]-_pre)

If it's not your expected output, please share more detail information to help us clarify your scenario.

Best Regards,
Eyelyn Qin
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

[Karlie69]

Thank you very much! It works 🙂 I just changed the formula from SUM to AVERAGE, because in some places I had bad results, but now it's good everywhere.

[Anonymous]

Hi @Karlie69 ,

According to your dataset screenshots, the Avr is in the same year of each Part_no, so how to calcualte the difference ?

Best Regards,
Eyelyn Qin

[Karlie69]

@Anonymous 

Sorry, this is my mistake. For the purposes of this post, I created an example dataset. The fourth line should be 2021.

I would just like to add a calculated column like in Excel pivot tables that will calculate the difference for me between 2021 and 2020. But is it better to make a pivot table in Power Query and calculate the difference there?

I did not think about it before - even if I create this column with DAX, it will not appear next to 2020 and 2021 in the table, but under these years.

[amitchandak]

@Karlie69 , Try new column like

New column =
var _max = maxx(filter(Table, [part number] = earlier([part number]) && [year] = earlier([year]) -1), [Avr. Currency Price])
return
[Avr. Currency Price] -_max

[Karlie69]

Hi @amitchandak ,

thanks for your answer. Unfortunately, it doesn't work and I don't know why.

I created the formula like this: