Why the measure returns error "A table of multiple values was supplied where a single value..."?

[darkmetrics]

Good afternoon!
I have a measure which calculates sales MTD, QTD or YTD and depends on slicer SalesDateSlicer value:

MyMeasure :=

var Result =
SWITCH
(
    SELECTEDVALUE(SalesDateSlicer[Period]),
    "MTD", CALCULATE(SUM('Sales'[Sales]), 
                     FILTER(ALL('Sales'),
                            DATESMTD('Sales'[Date]))
           ), 
    "QTD", CALCULATE(SUM('Sales'[Sales]), 
                     FILTER(ALL('Sales'),
                            DATESQTD('Sales'[Date]))
                    ),                         
    "YTD", CALCULATE(SUM('Sales'[Sales]), 
                     FILTER(ALL('Sales'),
                            DATESYTD('Sales'[Date]))
    )
)

RETURN Result 

 However, when I try to use my measure in a matrix it fails with error "A table of multiple values was supplied where a single value was expected". How to fix that?

[tamerj1]

Hi @darkmetrics 
Please try

MyMeasure :=
VAR Result =
    SWITCH (
        SELECTEDVALUE ( SalesDateSlicer[Period] ),
        "MTD",
            CALCULATE (
                SUM ( 'Sales'[Sales] ),
                DATESMTD ( 'Sales'[Date] ),
                ALL ( 'Sales' )
            ),
        "QTD",
            CALCULATE (
                SUM ( 'Sales'[Sales] ),
                DATESQTD ( 'Sales'[Date] ),
                ALL ( 'Sales' )
            ),
        "YTD",
            CALCULATE (
                SUM ( 'Sales'[Sales] ),
                DATESYTD ( 'Sales'[Date] ),
                ALL ( 'Sales' )
            )
    )
RETURN
    Result

However, this is not guaranteed to work as time intelligence functions require standard date table with homogeneous date column. It is always a good idea to use a dimension date table.