Redundant functions HASONEVALUE/SELECTEDVALUE, duplicated expression in arg. 2 of inner IF and arg. 3 outer IF)

The expression involving HASONEVALUE and SELECTEDVALUE functions can be optimized by removing HASONEVALUE, reducing the redundant expression in the second argument of the inner IF function and the third argument of the outer IF function.

Remarks

SELECTEDVALUE returns a non-blank value when there is only one value visible in the referenced column. Embedding SELECTEDVALUE in a condition related to HASONEVALUE seems redundant: removing HASONEVALUE can slightly improve the performance.

The third argument of both IF functions is duplicated, which allows to rely on the inner IF functions also for the cases covered by the outer IF function.

Example

Remove the outer IF function, the HASONEVALUE condition, and the third argument of the outer IF function. Assign VALUES to a variable, use COUNTROWS to count the values returned and use a single condition with these variables to check whether the common expression Sales Amount should be returned.

Original code

IF (
    HASONEVALUE( Customer[Country] ),
    IF (
        SELECTEDVALUE( Customer[Country] ) = "Canada",
        [Sales Amount],
        BLANK()
    ),
    [Sales Amount]
)

Possible optimization

VAR _SelectedValues = VALUES ( Customer[Country] )
VAR _NumberOfSelectedValues = COUNTROWS ( _SelectedValues )
RETURN
    IF ( 
        (_NumberOfSelectedValues = 1 && _SelectedValues = "Canada")
            || _NumberOfSelectedValues <> 1,
        [Sales Amount],
        BLANK ()
    )