50 day rolling average in ETL? Is it possible.

KenTravels

I have seen solution to a 5 day rolling average with 5 lines of code to build to 5 days, gets big with a 50 day average

 

Do not want create 50 extra columns to build the rolling average.  

RACERX

Not sure of specifics, but you could use a sub-query (MySQL/Redshift) or fork your MagicETL to filter for (roughly) `Your Data Date` <= CURRENT_DATE - '50 Data Days' then take an AVG of whatever the quantity column is. Once you have that, join it back to the main query or branch.  Assuming your data updates daily/regularly, then this average should stay current. 

jaeW_at_Onyx

do you HAVE to have it in ETL?  b/c you could shape your data by creating a Date Dimension

with two columns Report Date and Activity Date, such that the report date has A Day, and for each day in the Report Date you trail 50 days.

 

So if my Date table had 5 consecutive ReportDates, it'd have 5 * 50 (trailing) Activity dates.  for a total of 250 rows.

 

Then JOIN that to your fact Table on the Activity Date = Posting Date using a Fusion.  Then you can put Report Date on the Analyzer axis, and Avg (amount) or whatever.

 

You can do the same in ETL... but don't... writing a table exploded 50x is foolish.  also if you hardcode the rolling average, then it won't respond to filters.