Count rows with different tables

Hi DjZijlstra ,

This is because I did not de-duplicate the TbIContract[MainUnitID] column, please try the modified measure:

count the units with contract = 
VAR tab_contract =
    FILTER (
        TbIContract,
        AND (
            TbIContract[DateContractFrom] <= MAX ( 'dates'[date] ),
            OR (
                TbIContract[DateContractTo] >= MAX ( 'dates'[date] ),
                TbIContract[DateContractTo] = 0
            )
        )
    )
VAR tab_units =
    FILTER (
        TbIUnits,
        AND (
            TbIUnits[ExploitationDateForm] <= MAX ( dates[date] ),
            OR (
                TbIUnits[ExploitationDateTo] >= MAX ( dates[date] ),
                TbIUnits[ExploitationDateTo] = 0
            )
        )
    )
RETURN
    CALCULATE (
        DISTINCTCOUNT(TbIContract[MainUnitID]),
        tab_contract,
        tab_units,
        USERELATIONSHIP ( TbIUnits[UnitID], TbIContract[MainUnitID] )
    )

If the problem is still not resolved, please provide detailed error information or the expected result you expect. Let me know immediately, looking forward to your reply.
Best Regards,
Winniz
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