The expression refers to multiple columns. Multiple columns cannot be converted to a scalar value.

mansiluthra12 

You add a column, the result of your formula is supposed to produce one value, On which table are you adding column? May you need to get the maximum of the result as follows. Please check: Share the screenshot of your table and the new column

total =
MAXX (
    ADDCOLUMNS (
        VALUES ( Work[Date] ),
        "Day",
            CALCULATE ( DISTINCTCOUNT ( Work[ID] ), Work[Day] = 1, Test[testValue] = "abc" )
    ),
    [Day]
)

Hi mansiluthra12 ,

I think you need a FILTER expression within your CALCULATE function.

total =
    ADDCOLUMNS ( VALUES ( Work[Date] ), "Day", 
                 CALCULATE(
                           DISTINCTCOUNT(Work[ID]),
                           FILTER(Work, Work[Day] = 1) ,
                           FILTER(Test[testValue] = "abc") 
                          )
               )

I haven't tested the DAX, just re-wrote it.

Thanks,

Pragati