Why does DISTINCTCOUNT of Months have 1 extra count?

[Anonymous]

Hi,

I've built a Calendar table for use in a Power BI report and I want to create a measure that counts the number of months for the selected year in 2 slicers. Months & Years in the future are hidden/blank in Calendar. However, when I select Years from 2019 onwards my count has an extra value

ie my Measure (MthCount) counts as follows with no Months selected:

2017 - 12 months

2018 - 12 months

2019 - 8 months

2020 (onwards) - 1 month

Then, when I select say 2 Months my Measure counts correctly ie 2.

(see attached pics)

Does anyone know what's going on here?

Cheers

[d_gosbell · Accepted solution]

I think this is because you are force an explicit blank into that column for future periods. So 2020 has one blank for the TDYearMonth column and 2019 has 7 "real" months plus the blank which equals 8. So you could either filter out the blanks or use a different approach like creating a separate columns for filtering and counting.

MthCount = COUNTROWS( FILTER(VALUES('Calendar'[TDYearMonth]), NOT(ISBLANK('Calendar'[TDYearMonth]))))

or create a calculated column like the following:

IsPriorDate = IF( 'Calendar'[Date] <= Today(), 1,0)

Then you could add IsPriorDate = 1 as a Page or Report level filter.

[Anonymous]

@d_gosbell 

Brilliant! Thanks for that mate. I used your first solution ie filter inside my measure and it worked perfectly. Something I hadn't thought of in that forcing a BLANK basically created a 'value'. I'm still new to PBI so this is a good early learning experience.

Thanks again.