Difference between rows - for more than one columns in Power BI

Question

I am new to Power BI.

I am working on a task where I need to find the difference between two rows. There are multiple columns.

For a selected date,

   Date Attribute   Class1  Class2  Class3  Total
30/06/2021  T1  20  30  40  90
30/06/2021  T2  10  15  60  85
01/07/2021  T1  40  30  40  110
01/07/2021  T2  50  40  30  120

I want to find a way to get a T3 (is T2-T1 on a selected day) as below

Expected Output:

30/06/2021  T3 -10 -15  -20 -5
01/07/2021  T3  10  10  -10  10

Please help

Answer 1

Your expected output can be achieved by create a new table as summary:

First, obtain unique data from the table by create new table:

Table = DISTINCT(Sheet1[Date])

Second, create a new column by typing "T3":

Name = "T3"

The new table with basic data before calculation:

Next, calculate the difference between T1 and T2 on class1:

Class1 = CALCULATE(SUM(Sheet1[Class1]),
            FILTER(Sheet1,Sheet1[Date]=EARLIER('Table'[Date])),Sheet1[Attribute]="T2") - 
                CALCULATE(SUM(Sheet1[Class1]),
                    FILTER(Sheet1,Sheet1[Date]=EARLIER('Table'[Date])),Sheet1[Attribute]="T1")

To calculate the difference for class is using the same formula as above:

Class2 = CALCULATE(SUM(Sheet1[Class2]),
            FILTER(Sheet1,Sheet1[Date]=EARLIER('Table'[Date])),Sheet1[Attribute]="T2") - 
                CALCULATE(SUM(Sheet1[Class2]),
                    FILTER(Sheet1,Sheet1[Date]=EARLIER('Table'[Date])),Sheet1[Attribute]="T1")

Here is the final output, you can calculate the rest difference as above: