Count column value based on multiple criteria in another table

Hey ClemFandango ,

as I understand, you want the result as calculated column, is that right?
Try the following calculated column:

Count = 
VAR _DateCurrentRow = Table1[Date]
VAR _IDCurrentRow = Table1[ID]
VAR _FilterTable2 = FILTER( Table2, [Start] <= _DateCurrentRow && [End] >= _DateCurrentRow && Table2[ID] = _IDCurrentRow)
VAR _Result = COUNTROWS( _FilterTable2 )
RETURN
_Result

If you need any help please let me know.
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Best regards
Denis

Blog: WhatTheFact.bi
Follow me: twitter.com/DenSelimovic

Hi, ClemFandango 

Maybe you can use the follow DAX :

Count = 
VAR _count=CALCULATE (
    COUNT ( 'Table2'[ID] ),
    FILTER ('Table2',
       RELATED(Table1[Date]) >= 'Table2'[Start]
            && RELATED(Table1[Date]) <= 'Table2'[End]
              && Table2[ID] = [ID]
                       ))
RETURN
IF(_count> 0,
_count,
 0)

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