Forum Discussion
Helper VDAX YTD Different end dates per channel - data dates consistency problem
Hi there,
I have been given an interesting task to update our current YTD totals.
TYTD = This Year to Date
PYTD = Previous Year to Date
here is the YTD Measure:
TYTD UNITS = TOTALYTD([TOTAL UNITS],'CALENDAR'[DATE])
The TOTAL UNITS Measure is as follows:
TOTAL UNITS = SUM('FACT'[UNITS])These are my tables, (Star configuration)
- FACT
- PRODUCTS (The product link table is just to link up the products as the same product has 2-3 ID's)
- PLACES (KNOWN as MASTER_SITE)
- CALENDAR
Inside the MASTER_SITE (PLACES) table, I have a column called CHANNEL Different retail groups). - There are 4 channels.
For each channel, the data is updated on different periods, i.e. GROUP 1 gets updated daily, GROUPS 2-3 Get updated Monthly at the end of the Month, and GROUP 4 gets updated monthly the following month, thus when I do the TYTD calculation I get the latest YTD Units.
However when I want to work out the growth from this year vs Previous year - I use the following calculation:
TYTD UNITS GROWTH = DIVIDE([TYTD UNITS]-[PYTD UNITS],[PYTD UNITS])
The PYTD Measure is as follows:
PYTD UNITS = TOTALYTD([TOTAL UNITS],SAMEPERIODLASTYEAR('CALENDAR'[DATE]))This is where the problem I am facing is, as the different Channels/Groups have different date periods it is not giving me a fair TYTD UNITS GROWTH Results as the PYTD UNITS is taking all the months data from each of the channels (i.e. 2016-01 to 2017-07) and the TYTD UNITS is taking the following:
- GROUP 1 2016-01 to 2017-07 - this is fine as the previous year data is consistent
- GROUP 2-3 is measuring (PYTD = 2016-01 to 2017-07) against (TYTD = 2017-01 to 2017-06) - this is not fine as there is a month missing, thus the previous year should only go up until 2017-06 as there is not data for these groups in 2017-07 yet.
- GROUP 4 is measuring (PYTD = 2016-01 to 2017-07) against (TYTD = 2017-01 to 2017-05) which is the same problem as the above 2 groups but worse off by another month.
so I am looking for a way to update the TYTD UNITS GROWTH and the PYTD UNITS measures in order for them to take into account the latest date contest for/within the different Channels.
Looking forward to hearing back from anyone.
Regards,
Mark B
Here is an example of how I would do it.
I've used your Excel data posted earlier.
The logic is to iterate over the values of Channel using SUMX, and for each Channel determine the last date for which data exists, and if that date is earlier than the last selected date, cut off the PYTD calculation at that date.
The PYTD UNITS measure looks like this:
(Note: I would have written this slightly differently using TREATAS, but there seems to be a bug with TREATAS in Power BI Desktop at the moment)PYTD UNITS = SUMX ( VALUES ( CHANNEL[CHANNEL] ), // Iterate over CHANNELs VAR CalendarLastDateSelected = MAX ( 'CALENDAR'[DATE] ) // Last date selected on CALENDAR table VAR ChannelLastDateGlobal = CALCULATE ( MAX ( 'FACT'[DATE] ), ALLEXCEPT ( 'FACT', 'CHANNEL' ) ) // Last date that exists in FACT for the current CHANNEL (ignoring any filters other than CHANNEL) VAR ChannelLastDateApplied = MIN ( CalendarLastDateSelected, ChannelLastDateGlobal ) // The earlier of these is the date to apply for PYTD calculation RETURN CALCULATE ( [TYTD UNITS], SAMEPERIODLASTYEAR( 'CALENDAR'[DATE] = ChannelLastDateApplied ) ) )You might also want to edit the measures so that YTD or PYTD values are hidden per channel for dates later than the maximum existing date, using the method on this page:
http://www.daxpatterns.com/cumulative-total/
Regards,
Owen
17 Replies
Hi MarkCBB,
Can you please share some sample data that has various channel & update dates dates so that i can replicate the same at my end & help you in a more intutive way??
Regards
