virtual table create with next contact columns

[Fiala]

Hi, I'm already desperate. I need advice on the next task. I want to create a virtual table. In the table, create a new column named Next Contact. I want to know when the number in the CD_MSISDN column called the next one again if it called. I can't find the right results. 

I try more measures.. Fox example.
DEFINE
var curr_CD_MSISDN = max(Query1[CD_MSISDN])
var this_date = CALCULATE(min(Query1[TS_ENTERED_QUEUE]),filter(Query1,Query1[CD_MSISDN]=curr_CD_MSISDN))
    VAR v1 =
        ADDCOLUMNS (
            SUMMARIZE ( Query1, Query1[CD_MSISDN], Query1[TS_ENTERED_QUEUE] ),
            "NEXT Contact",
                CALCULATE (
                    CALCULATE(min(Query1[TS_ENTERED_QUEUE]),ALLEXCEPT(Query1,Query1[CD_MSISDN])
                   ,Query1[TS_ENTERED_QUEUE]>this_date)
                )
        )

EVALUATE
v1
This returns. 

Red is an example of the correct result. I think the problem is in setting the correct filter context for the variables "Curr_CD_MSISDN" and "this date". But I can't solve it. Can anyone please advise me?

[Fiala]

@d_gosbell 

Thank you for your help. The calculation needed a little adjustment but I'm already getting the right results. It never occurred to me that there might be such a problem.

DEFINE
    VAR v1 =
        ADDCOLUMNS (
            SUMMARIZE ( Query1, Query1[CD_MSISDN], Query1[TS_ENTERED_QUEUE] ),
            "NEXT Contact",
                VAR curr_CD_MSISDN =
                    MAX ( Query1[CD_MSISDN] )
                RETURN
                    CALCULATE (
                        MIN ( Query1[TS_ENTERED_QUEUE] ),
                        ALLEXCEPT ( Query1, Query1[CD_MSISDN] ),
                        Query1[TS_ENTERED_QUEUE] > EARLIER(Query1[TS_ENTERED_QUEUE]))
                    )
        

EVALUATE
v1

[d_gosbell · Accepted solution]

The problem here is that you are declaring the this_date variable at the top of the query, so it gets evaluated once at the start of the query. Whereas you really need to be evaluating it for each row.

So you should be able to more the VAR/RETURN inside the expression for the "NEXT Contact" column so that the two variables get re-calculated for each row in the result set.

DEFINE

    VAR v1 =
        ADDCOLUMNS (
            SUMMARIZE ( Query1, Query1[CD_MSISDN], Query1[TS_ENTERED_QUEUE] ),
            "NEXT Contact",
                var curr_CD_MSISDN = max(Query1[CD_MSISDN])
				var this_date = CALCULATE(min(Query1[TS_ENTERED_QUEUE]),filter(Query1,Query1[CD_MSISDN]=curr_CD_MSISDN))
                return CALCULATE(min(Query1[TS_ENTERED_QUEUE]),ALLEXCEPT(Query1,Query1[CD_MSISDN])
					,Query1[TS_ENTERED_QUEUE]>this_date
				)
        )

EVALUATE
v1

another approach is to put the Next Contact calculation into a measure, then reference that from in your table.

DEFINE
Measure Query1[NEXT Contact] = 
var curr_CD_MSISDN = max(Query1[CD_MSISDN])
var this_date = CALCULATE(min(Query1[TS_ENTERED_QUEUE]),filter(Query1,Query1[CD_MSISDN]=curr_CD_MSISDN && Query1[TS_ENTERED_QUEUE]>this_date))
RETURN this_date
    VAR v1 =
        ADDCOLUMNS (
            SUMMARIZE ( Query1, Query1[CD_MSISDN], Query1[TS_ENTERED_QUEUE] ),
            "NEXT Contact",
            [NEXT Contact]
        )

EVALUATE
v1