countrows with filter issue

[Yiling]

Hi Expert,

would appreciate if someone can shed some light on this problem I'm struggling with.

Background

i have two tables 

1. daily services - train daily services info

2. vds - crew shift info

i build a bridge table to link daily services & vds by using UniqueKey which is merged from two columns 

in daily services is operating date & TT_TDN

in VDS is shiftdate &TripID

i have a measure to calculate the number of first departure train services 

First Departure = CALCULATE(COUNTROWS('COMPASS VU_DailyServices'),FILTER('COMPASS VU_DailyServices','COMPASS VU_DailyServices'[First Departure]=1))

i also have a test first departure measure

Test.FD = CALCULATE(COUNTROWS('v_VDS_Compass_2'),FILTER('COMPASS VU_DailyServices','COMPASS VU_DailyServices'[First Departure]=1))

this two DAX supposed return to the same result, because each train crew run one service, 

but i receive two different result, only first departure gives me right number.

but when i add columns - depot from vds table, the first departure from each depot = test first departure, the number at each depot largely decreased.

here's my pbix link for test

https://1drv.ms/u/s!AjpB2wk5YDY3hwObjTB22ZdetGwb?e=rK1Bb9

thanks 🙂 

[v-shex-msft · Accepted solution]

Hi @Yiling,

I think this should be related to the relationship between two tables, measure will apply filter effects through related fields.
How did your table field links? (relationship mapping and direction)

You can also take a look at the following link to know more about relationship mapping.

What is the Direction of Relationship in Power BI? 

Create and manage relationships in Power BI Desktop 

Regards,

Xiaoxin Sheng