How can I calculate market share for a segment by selecting one or more products in one or more segments?

Question

I'm attempting to calculate market share (percentage of total) for a segment after a user selects a specific product within a filter.

Data looks like this:

Date	Product	Segment	Volume
Jan 1	Bike	Sports	10
Feb 1	Bike	Sports	11
Mar 1	Bike	Sports	14
Jan 1	Helmet	Protective Equipment	9
Feb 1	Helmet	Protective Equipment	2
Mar 1	Helmet	Protective Equipment	3
Jan 1	Kneepads	Protective Equipment	10
Feb 1	Kneepads	Protective Equipment	4
Mar 1	Kneepads	Protective Equipment	12

I have a measure to calculate the total volume of the segment, defined as:

Total Volume of Segment =
IF (
    HASONEVALUE ( 'Table'[Product] ),
    CALCULATE (
        [Sum of Volume],
        FILTER (
            ALLEXCEPT ( 'Table', 'Table'[Segment] ),
            VALUES ( 'Table'[Segment] ) = [Segment of Product]
        )
    ),
    CALCULATE ( [Sum of Volume], ALL ( 'Table' ) )
)

The measures within are defined as:

Sum of Volume = SUM( 'Table' [Volume])

&

Segment of Product = IF(HASONEVALUE('Table'[Product]), CALCULATE(VALUES('Table'[Segment])), BLANK())

This is functioning as expected, you can see here:

However, I'm observing unexpected behaviour when a filter is selected:

If a single product is selected, the measure calculates correctly and sums up the total volume in all the products belonging to the same segment:

However, if multiple products are selected (whether they're in the same segment or different segment), the total that is returned is the sum of all the products disregarding all of the applied filters:

Any help on how to re-write the measure to validate multple selections is greatly appreciated.

Answer 1

Try changing your ALL to ALLSELECTED:

Total Volume of Segment = 
IF (
    HASONEVALUE ( 'Table'[Product] ),
    CALCULATE (
        [Sum of Volume],
        FILTER (
            ALLEXCEPT ( 'Table', 'Table'[Segment] ),
            VALUES ( 'Table'[Segment] ) = [Segment of Product]
        )
    ),
    CALCULATE ( [Sum of Volume], ALLSELECTED( 'Table' )
)

)