Compare 2 months using Slicer

[rui_silva]

Hi,

i have a table where i need to compare values from 2 months using slicer, at this moment im using this measure:

Total LM = CALCULATE([nStudents];PREVIOUSMONTH('Month'[Data]) ) when i try to use this measure i dont get any result.

Sample Data

Data                        ClassName     nStudents       Total LM

01/01/2018               ClassA                30                  

01/02/2018               ClassA                25                  -5

My Month[Data] its already set as data table if it helps.

At my relationship i have

My class table as * to 1 for Month table.

My class table has IdMonth .

Rui Silva

[Greg_Deckler]

So, the sample data you presented, is that what you want to display as far as the Total LM, but you are not getting that result?

[rui_silva]

@Greg_Deckler Yes

[Greg_Deckler]

OK, so is the sample data presented (other than Total LM) represent your source data or are there some calculations going on there? So do you have 1 row for each month in your source data?

[rui_silva]

@Greg_Deckler So in my source data i have for each class 4 rows with diferent data and month as for example:

IDMonth IDClass ClassName        nStudents

1               CA       ClassA                      30

1               CB        ClassB                      30

2              CA          ClassA                     25

2               CB          ClassB                    25

3              CA         ClassA                     25

3               CB         ClassB                     20

4               CA          ClassA                    25 

4               CB         ClassB                      19

This is my source data the only calculation i had was the total os nStudents, and when i try to compare the months each others  when i put the measure in the table the result dont appear, Also i have Month table as Source

IDMonth        MonthName        Date

1                          January            01/01/2018

2                           February          01/02/2018

3                          March               01/03/2018

4                           April                 01/04/2018

My date column is formated to be the data table so i could compare the months.

[Greg_Deckler]

OK, so since you do not have a true Date column, you are probably going to run into issues with the standard time intelligence functions. Check out my Time Intelligence "The Hard Way" Quick Measure here:

https://community.powerbi.com/t5/Quick-Measures-Gallery/Time-Intelligence-quot-The-Hard-Way-quot-TIT...

[rui_silva]

@Greg_Deckler  First of all Thanks for  the assistance,

About true Date Column what u mean with that ? 

Its is a column made with Dax / Power Query ?

[rui_silva · Accepted solution]

@Greg_Deckler Thanks for all the help,

I managed to get solution using a invoked table with dates from 01/01/2018 to 31/12/2018 and its working as i would understand everytime i need to compares dates i cant uses tables i used from myself and need to create a invoked table with dates , etc 

Thanks ! 

Rui Silva