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Element115's avatar
Element115
Memorable Member
4 years ago

DAX interpreter BUG!!!

The following (code in red) works when run in the Power Bi Desktop version, but as soon as you replace it by the variable name, which contains the same code, Power BI generates an error.  In a nutshell, the column [UnreachableSince] is of data type TEXT containing textual representations of DATETIME values and other non-datetime values (I know and there is nothing I can do about this).


To intercept the DATETIME values, therefore an IF() is used.  It all works fine until you decide to use the variable name in place of the inline code inside the nested IF().

So this OK:

DATEDIFF(DATEVALUE([UnreachableSince]) + TIMEVALUE([UnreachableSince]), [ClosedDT], SECOND)


But this NOT OK!

DATEDIFF(__unreachable_dt, [ClosedDT], SECOND),

 

Code here (sorry but can't add colors when using Insert/Edit code sample from this editor toolbar):

 

ADDCOLUMNS(
    GROUPBY(
       ADDCOLUMNS(
            CALCULATETABLE(
                 SELECTCOLUMNS(
...
                 ),
            FILTER(
...
            )
),
"DownTime", IF ( [ErrorCategory] == "Unreachable",
                         VAR __unreachable_dt = DATEVALUE([UnreachableSince]) + TIMEVALUE([UnreachableSince])
                         VAR __unreachable_dt_in_secs = DATEDIFF(__start_date, __unreachable_dt, SECOND)
                         RETURN
                               IF( __unreachable_dt_in_secs >= 0,
                                     DATEDIFF(DATEVALUE([UnreachableSince]) + TIMEVALUE([UnreachableSince]), [ClosedDT], SECOND),
                                     BLANK() //DATEDIFF([CreationDT], [ClosedDT], SECOND)
                                ),
                          DATEDIFF([CreationDT], [ClosedDT], SECOND)
                     )
),
[AssetName],
"DownTime", SUMX(CURRENTGROUP(), [DownTime])
),
"% up", 1 - ([DownTime] / __in_service_time)
)

 
So am I imagining things, or isn't this a DAX interpreter bug?


DAX BUG

5 Replies

      • Element115's avatar
        Element115
        Memorable Member
        4 years ago

        TBH what you are saying makes no sense to me:  variables 

        are evaluated in the context in which they are written.

         

        Variables should be visible in the scope in which they are declared, period.  Are you saying that DAX scoping isn't following what we are used to with all major programming languages out there?  

         

        In any case, all my variables are usually declared top level, ie right after the 'MeasureName = ' line.  Therefore I would expect this scope to be visible all the way down to the RETURN statement.

        Isn't it so?