Calcuate days between two dates without rows missing

[Anonymous]

Tried to use this DAX expression:

DateDiff =

                   var DF = 1. * ([StartDate] - [EndDate])

                   return IF([StartDate] <> BLANK(), DF, TODAY())

Not all Rows have value on Column [StartDate] and [EndDate].  With Today() in DAX, will return all rows. However, without Today() in Dax, will return only those Rows with [StartDate] value. I don't want Today() value in column DateDiff and fill in Blank Value instead. 

What DAX expression can make it

[Greg_Deckler · Accepted solution]

@Anonymous Try returning BLANK() but then set the Show items with no data:

[Greg_Deckler · Accepted solution]

@Anonymous Try returning BLANK() but then set the Show items with no data:

[Anonymous · Accepted solution]

Yes, Blank() works when checked "Don't summarize". Thx