Compare previous and new sales

[diddlmus]

Hi All

Im trying in Power BI to create a report with yesterdays sales compared to the same day last year.

I managed to make a report showing the sale from day this year and the sale from the same day last year.

I got them sorted by our stores. Så i have the stores in rows and the 2 dates in the columns with their sales. Now i want a third column with the difference between the 2 numbers, and i cant figure out how to do that - everything i have tried that gets remotely close to what i want to achieve makes an column with a difference after the 2015 date and the 2016 date - i only want a single column at the end showing the difference.

STORE-->SALES YESTERDAY-->SALES SAME DAY LAST YEAR-->DIFFERENCE BETWEEN

I tried searching for a solution but cant find one that comes close enough to what i want to achieve.

Hope somebody can help.

[v-sihou-msft]

@diddlmus

Generally, we can make the dataset with columns of Date, Store and Sales as below.

Then we can create a calculated column “Diff_PY_Sales” with following formula to get the difference of sales between day this year and the same day last year.

Diff_PY_Sales =
VAR PY_Sales =
    CALCULATE (
        SUM ( Table1[Sales] ),
        SAMEPERIODLASTYEAR ( Table1[Date] ),
        ALLEXCEPT ( Table1, Table1[Store] )
    )
RETURN
    (
        IF (
            SAMEPERIODLASTYEAR ( Table1[Date] ) <> BLANK (),
            Table1[Sales] - PY_Sales,
            BLANK ()
        )
)

Regards,