Need to identify repeating tasks within a 30 day period

[Iryna_Khomenko]

Dear experts, 

Can you please help me with this: I have a table with tasks IDs, their end dates, machines(projects we call them) that these tasks were done for, technicians who completed those tasks. 

We are tracking the "repetitive" tasks that occur more than once within a month (because that'd mean they have not been done properly the first time around).

I now have the count of those like so: 

Count of repetitive tasks =

    CALCULATE (

        SUMX ( FILTER ( 'Dim - Project', [Count of tasks] > 1 ), [Count of tasks] ))

But I need more information about the tasks, not just the count (the technician, for one). What I am thinking now is that I need to rank them by order of their end dates within the past 30days. So that I could see who's done it the first time, who's done it the second time, etc. Please advise. Also there's this 30 days rolling window - current solution "cuts" the calculations at the period selected in the slicer (if it's 2023.01 - then all that happens within Jan), but I need to rebuild it so that it evaluates the tasks for each day of Jan - 30 days, i.e. the task that appears first time in Jan could in fact be repetitive because it's been already done at the end of December so I need to count it as a repetitve task in Jan. The task IDs are unique, so they don't repeat, whether they are repetitive or not we define as follows: if it was done to the same "project" within 30days. In advance, HUGE THANKS!

[Iryna_Khomenko]

I redesigned the approach to this issue. Please see the sample of data below. What I need now is to add three columns: previous end date, previous idd_tk_user, and time difference (current row's End Date - Previous End Date) that would add a previous idd_tk_user, a previous End date, and the time difference between end dates if the task type title is not "Filling the vending machines". So we find the latest non-vending task for the selected project and map to it the end date and the user for the previous non-vending task. In advance, thank you kindly!