Check if value exists in group

Hi Attrywa ,

Please try:

Create a calculated column in Table A:

Flag =
VAR CurrentGroup = 'Table A'[LogGroupKey]
VAR LogKeyCheck = CALCULATE(
     MAXX(
         RELATEDTABLE('Table B'),
         IF('Table B'[LogKey] = 124, 1, 0)
     ),
     FILTER(
         'Table B',
         'Table B'[LogGroupKey] = CurrentGroup
     )
)
RETURN IF(LogKeyCheck = 1, 1, 0)

The page effect is as follows:

pbix file is attached.

If you have any further questions please feel free to contact me.

Best Regards,
Yang
Community Support Team

If there is any post helps, then please consider Accept it as the solution  to help the other members find it more quickly.
If I misunderstand your needs or you still have problems on it, please feel free to let us know. Thanks a lot!

Attrywa 

you can create a column

Column = if(ISBLANK( maxx(FILTER(TableB,TableB[LogKey]=124&&TableA[LogGroupKey]=TableB[LogGroupKey]),TableB[LogKey])),0,1)

 

or a measure

Measure =

if(ISBLANK(maxx(FILTER(all(TableB),'TableB'[LogGroupKey]=max('TableA'[LogGroupKey])&&'TableB'[LogKey]=124),TableB[LogKey])),0,1)

 

 

pls see the attachment below