count distinct

Another method would be to use the time column of your data as a slicer, select for the current year.

Meanwhile, place your customers in the visual (table for exemple) and select count (distinct) in the summarization pannel :

Hi Carlaf 

It's not clear where you want to place these two measures for comparison.

Suppose we have a table like this.

1. If placed in a same visual for comparison, you can use [Year] as the axis and put the measure [customer's_today] in the value field.

2. If you want to compare this year's value with last year's value and compare the measures in two different visualizations, please try.

customer's_last_year1 = 
CALCULATE (
    DISTINCTCOUNT ( CUSTOMERS_DETAILS[CUSTOMER] ),
    SAMEPERIODLASTYEAR ( DATESYTD ( STAT_VEN[TMPDDATA] ) ),
    FILTER ( STAT_VEN, STAT_VEN[sales_this_year] > 0 )
)

or

customer's_last_year2 = 
CALCULATE (
    DISTINCTCOUNT ( CUSTOMERS_DETAILS[CUSTOMER] ),
    PARALLELPERIOD('STAT_VEN'[TMPDDATA],-1,YEAR),
    FILTER ( STAT_VEN, STAT_VEN[sales_this_year] > 0 )
)

3.  Comparison of the same period.

customer's_last_year3 = 
VAR _last_date =
    LASTDATE ( 'CUSTOMERS_DETAILS'[DateCloumn] )
VAR _result =
    CALCULATE (
        DISTINCTCOUNT ( CUSTOMERS_DETAILS[CUSTOMER] ),
        SAMEPERIODLASTYEAR ( DATESYTD ( _last_date ) ),
        FILTER ( STAT_VEN, STAT_VEN[sales_this_year] > 0 )
    )
RETURN
    _result

Best Regards,
Gao
Community Support Team

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