Find the Distinct Value based on other columns

[timstacy1]

Hi,

I want to create a dax formula that will produce a list of unique guest values from Column A, and find only the distinct value in column B (Host) based on the latest date.  The final report will only have a list of distinct guests and one host per guest.  Although, I would expect to see multiple hosts from the entire list.  The answer below should be as follows:

Server A has a Host A because the last report date is 04/17/2017.

Thank you,

Tim

Guest	Host	Report Date
server A	Host A	4/17/2017
server A	Host B	4/10/2017
server A	Host C	4/3/2017
server A	Host D	3/20/2017
server A	Host E	2/20/2017
server A	Host F	2/13/2017

[v-ljerr-msft · Accepted solution]

Hi @timstacy1,

It seems that there are some Guests have multiple Hosts with the same last Report Date. For example, Server A has both Host A and Host B with the last report date 04/17/2017 in your table like below.

Guest	Host	Report Date
server A	Host A	4/17/2017
server A	Host B	4/17/2017
server A	Host C	4/3/2017
server A	Host D	3/20/2017
server A	Host E	2/20/2017
server A	Host F	2/13/2017

So what's your expected result in this scenario, show only Host A, or both Host A and B for Server A in the list?

If you still need a list of distinct guests and one host per guest, the formula below show work in your scenario. 

HostLatestReport =
CALCULATE (
    FIRSTNONBLANK ( Table2[Host], 1 ),
    FILTER (
        ALLEXCEPT ( Table2, Table2[Guest] ),
        Table2[Report Date] = [LatestReport]
    )
)

Regards

[v-ljerr-msft · Accepted solution]

Hi @timstacy1,

It seems that there are some Guests have multiple Hosts with the same last Report Date. For example, Server A has both Host A and Host B with the last report date 04/17/2017 in your table like below.

Guest	Host	Report Date
server A	Host A	4/17/2017
server A	Host B	4/17/2017
server A	Host C	4/3/2017
server A	Host D	3/20/2017
server A	Host E	2/20/2017
server A	Host F	2/13/2017

So what's your expected result in this scenario, show only Host A, or both Host A and B for Server A in the list?

If you still need a list of distinct guests and one host per guest, the formula below show work in your scenario. 

HostLatestReport =
CALCULATE (
    FIRSTNONBLANK ( Table2[Host], 1 ),
    FILTER (
        ALLEXCEPT ( Table2, Table2[Guest] ),
        Table2[Report Date] = [LatestReport]
    )
)

Regards

[timstacy1]

Hello,

Thank you.  The measures generated the following erros:

MdxScript(Model)(10,49) Calculation error in measure 'allguests'[hostlatestreport]:  a table ofmultiple values was supplier where a single value was expected.

I have a long list of guest and host entries.  Could this be the source of the error?

Thank you,

Tim

[timstacy1]

You are correct.  I am only interested in a unique host for every unique guest, using the latest date as the determining factor.  My apologies for the flawed table but glad you figured it out.  I applied the measure and it worked!  I can't believe it.  I can't tell you what a help this is.   Now, I need to figure out why it works.  And, due to the size of the file I am working with, I run out of memory.  

Thank you again!

Tim

[v-ljerr-msft · Accepted solution]

Hi @timstacy1,

Glad to help! Could you accept helpful replies as solution to close this thread? 

Regards

[Vvelarde]

@timstacy1

Hi Friend, Check this measure:

LatestReport =
CALCULATE ( MAX ( Table2[Report Date] ), ALLEXCEPT ( Table2, Table2[Guest] ) )

HostLatestReport =
CALCULATE (
    VALUES ( Table2[Host] ),
    FILTER (
        ALLEXCEPT ( Table2, Table2[Guest] ),
        Table2[Report Date] = [LatestReport]
    )
)