Merge the values into one

Hi Prasad23 ,

You can try below calculated column expression.

Result 1 = 
VAR TempTable = 
    CALCULATETABLE(
        ADDCOLUMNS('Table',"diff",DATEDIFF('Table'[created date],'Table'[closed date],DAY)),
        ALLEXCEPT('Table','Table'[BU],'Table'[Sub_bu])
    )
VAR MinDiff = MINX(TempTable,[diff])
VAR MaxDiff = MAXX(TempTable,[diff])
RETURN
IF(MinDiff<>MaxDiff,MinDiff&" - "&MaxDiff&" days",MinDiff&" days")

Or is another result what you want?

Result 2 = 
VAR TempTable = 
    CALCULATETABLE(
        ADDCOLUMNS('Table',"diff",DATEDIFF('Table'[created date],'Table'[closed date],DAY)),
        ALLEXCEPT('Table','Table'[BU],'Table'[Sub_bu])
    )
VAR MinDiff = MINX(TempTable,[diff])
VAR MaxDiff = MAXX(TempTable,[diff])
VAR Result = IF(MinDiff<>MaxDiff,MinDiff&" - "&MaxDiff&" days",MinDiff&" days")
RETURN
IF(
    ROWNUMBER(
        ALL('Table'[BU],'Table'[Sub_bu],'Table'[created date],'Table'[closed date]),
        ORDERBY('Table'[created date],ASC,'Table'[closed date],ASC),
        PARTITIONBY('Table'[BU],'Table'[Sub_bu])
    )=1,
    Result
)

Demo - Merge the values into one.pbix

Did I answer your question? If yes, pls mark my post as a solution and appreciate your Kudos !

Thank you~