Calculating Difference from previous year

[adrianfer]

Good day, I need help please in calculating the column 'Difference from Previous Year'. Thank you in advance!

My data is like this (and also attached):

[hanna_choi]

Hello @adrianfer 

I solve this issues using "before()" functions.

expression : Sum(Count) - before(Sum(Count))

[anat · Accepted solution]

data:

load month ,year,count from table;

left join

load addmonths(month,1) as month,

count as pre_count

resident data;

in frontend use the sum(count)-sum(pre_count)

use the below for reference:

https://community.qlik.com/t5/App-Development/Previous-month-sales-in-loading-script/td-p/1697294