Summarize rows by time and result

Hi adinh - you can create a measure that identifies the latest timestamp for "Answered" , you can replace the table name as per your model.

LatestAnsweredTimestamp =
CALCULATE(
MAX(CallLog[Timestamp]),
FILTER(
CallLog,
CallLog[Result] = "Answered" && CallLog[Operator] = "Help Desk"
)
)

create another measure for no answer as like above without help desk condition.

LatestNoAnswerTimestamp =
CALCULATE(
MAX(CallLog[Timestamp]),
FILTER(
CallLog,
CallLog[Result] = "No Answer"
)
)

Now create last measure that chooses the row with the latest timestamp for "Answered" and, if no such result exists, defaults to "No Answer"

FinalTimestamp =
IF(
ISBLANK([LatestAnsweredTimestamp]),
[LatestNoAnswerTimestamp],
[LatestAnsweredTimestamp]
)

now you  can use the TopN function in DAX to pull the latest entry

TopNResult =
TOPN(
1,
CallLog,
[FinalTimestamp],
DESC
) 

it returns the latest answered. hope the above measure helps to achieve the same.

Hi adinh 

First of all, thank you rajendraongole1 for your positive reply!
Change the DAX formula for the "TopNResult" in the method provided by rajendraongole1 as follows:

TopNResult = 
SUMMARIZE(
    ADDCOLUMNS(
        CallLog,
        "FinalTimestamp", [FinalTimestamp]
    ),
    CallLog[NO.],
    "LatestTimestamp", MAXX(
        TOPN(
            1,
            FILTER(
                CallLog,
                CallLog[NO.] = EARLIER(CallLog[NO.])
            ),
            [FinalTimestamp],
            DESC
        ),
        [FinalTimestamp]
    ),
    "Operator", MAXX(
        TOPN(
            1,
            FILTER(
                CallLog,
                CallLog[NO.] = EARLIER(CallLog[NO.])
            ),
            [FinalTimestamp],
            DESC
        ),
        CallLog[Operator]
    ),
    "Result", MAXX(
        TOPN(
            1,
            FILTER(
                CallLog,
                CallLog[NO.] = EARLIER(CallLog[NO.])
            ),
            [FinalTimestamp],
            DESC
        ),
        CallLog[Result]
    )
)

Best Regards,
Jarvis Tang
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