Date difference in same column for different stage in text format

Hi Antonio195754 ,

I think there should be multiple projects which should be keynames and there are multiple stages in them.

Please try this code to create a calculated column.

DateDiff = 
VAR _PreviousDate =
    CALCULATE (
        MAX ( 'B Opportunity with History'[CREATEDATE] ),
        FILTER (
            ALLEXCEPT ( 'B Opportunity with History', 'B Opportunity with History'[Project] ),
            'B Opportunity with History'[CREATEDATE] < EARLIER ( 'B Opportunity with History'[CREATEDATE] )
        )
    )
VAR _DATEDIFF =
    DATEDIFF (
        IF ( _PreviousDate = BLANK (), 'B Opportunity with History'[CREATEDATE], _PreviousDate ),
        'B Opportunity with History'[CREATEDATE],
        DAY
    )
RETURN
    _DATEDIFF

Result is as below.

Best Regards,
Rico Zhou

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