why earlier function error

[Anonymous]

Hi, 

I want to calculate the total number of convid cases by date. however the formula below throws an error. I think it might relates to the language setup of my Power BI or my laptop. however, i don't know how to fix it. 

[Greg_Deckler]

That's odd, the error message doesn't seem to match. First question, is this supposed to be a measure or a column?

[Anonymous]

I meant to write a measure. 

[Greg_Deckler · Accepted solution]

OK, you generally don't use EARLIER in a measure unless you are using ADDCOLUMNS.

So, the next question, what are you trying to accomplish? If you just do SUM([Total confirmed cases of COVID-19] and you put that in a visual along with your Date column, you should get the total confirmed cases for every date. Is that what you want?

[Anonymous]

You are right. when I use the earlier function in the column calculation, it works!

I also remember the reason behind, ealier function scann the day column line by line to get the current "day" as a filter condition. Therefore it can only be used in column calculation.

[Greg_Deckler]

Yes, unless you use ADDCOLUMNS in a measure, then you can use EARLIER when adding a column.

[Anonymous]

I don't think earlier function is only used in new column. I have seen examples using earlier function to create a measure of sales revenue by product category, and use this measure to create visuals with slicers. 

In my case, i want to know how number of crono cases grows from day x to day x+1. Using China and Italy data, it turns out before lockdown, the crono cases increase 30-40% per day, 5 days after lockdown, the increase rate declines. i would like to see if it's the similar case with other countries. therefore i want to create the growth rate measure, track growth rate by days and country in power visual. 

[Greg_Deckler]

Yes, that's why I said generally! 🙂 It can be done, it is just not that common.

If I may make a suggestion, I would try something like:

% Growth = 
  VAR __Date = MAX('Table'[Date])
  VAR __Today = SUM([Total confirmed cases of COVID-19])
  VAR __Yesterday = SUMX(FILTER('Table',REMOVEFILTERS('Table'[Date]),[Date]=(__Date - 1) * 1.),[Total confirmed cases of COVID-19])
RETURN
  DIVIDE(__Today - __Yesterday,__Yesterday,0)

You should be able to place that into a visual along with Date.