Distinct count by max date

Hi,lnik 

I am glad to help you. 

According to your description, you want to distinct count by max date? 

If I understand you correctly, then you can refer to my solution. 

1. You can start by creating a new table. 

Table 2 = 
VAR _distinct =
    SUMMARIZE (
        'Table',
        'Table'[Item],
        'Table'[Customer],
        'Table'[Date Visit],
        "MaxDate",
            CALCULATE (
                MAX ( 'Table'[Date Visit] ),
                FILTER ( ALL ( 'Table' ), 'Table'[Item] = EARLIER ( 'Table'[Item] ) )
            )
    )
RETURN
    FILTER (
        _distinct,
        IF ( 'Table'[Item] = 3, BLANK (), 'Table'[Date Visit] = [MaxDate] )
    )

2. Create a Measure for calculating the number of rows corresponding to each Item, and you'll end up with the result you want. 

DistinctCount = 
VAR _currentItem =
    MAX ( 'Table 2'[Item] )
RETURN
    COUNTROWS ( FILTER ( ALL ( 'Table 2'[Item] ), 'Table 2'[Item] = _currentItem ) )

I hope my suggestions give you good ideas, if you have any more questions, please clarify in a follow-up reply.
Best Regards,
Fen Ling,
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