Count multiple columns include blanks

pardeepd84 You can use the and && operator and create a measure:

Count Rows = COUNTROWS( FILTER( 'Table', NOT(ISBLANK('Table'[ID])) && NOT(ISBLANK('Table'[Start date])) && NOT(ISBLANK('Table'[start time])) && NOT(ISBLANK('Table'[end time])) )

pardeepd84  You can try doing this as a calculated COLUMN (not measure) 

Result =

VAR _currentrowID = Table[ID]

VAR _CRstartDate = Table[Start Date]

VAR _CRstartTime = Table[Start Time]

RETURN

COUNTROWS( FILTER( Table, Table[ID] = _currentrowID  && _CRstartDate = Table[Start Date] &&  _CRstartTime = Table[Start Time]) )

pardeepd84 

If you add a + 0 to the end of your formula that should do it.

Results3 =
VAR _currentrowID = 'Table (2)'[ID]
VAR _CRstartDate = 'Table (2)'[Start Date]
VAR _CRstartTime = 'Table (2)'[Start Time]
RETURN
    COUNTROWS (
        FILTER (
            'Table (2)',
            'Table (2)'[ID] = _currentrowID
                && _CRstartDate = 'Table (2)'[Start Date]
                && _CRstartTime = 'Table (2)'[Start Time]
                && 'Table (2)'[ID] <> BLANK ()
                && 'Table (2)'[Start Date] <> BLANK ()
                && 'Table (2)'[Start Time] <> BLANK ()
                && 'Table (2)'[ID] = _currentrowID
                && 'Table (2)'[Start Date] = _CRstartDate
                && 'Table (2)'[Start Time] = _CRstartTime
        )
    ) + 0