Help with YoY % measure

[Dimps]

I am new to power BI. I am using the below formula. However when "PY TD MARKET SHARE" has sales and PY Total market share is $0, it is showing 0.00% which is not correct. it should show "100%" and when "PY TD MARKET SHARE" is $0 and PY Total market share has sales it is showing 0.00% iwhere as it should show -100%. 

IF(SUM('NPD workflow'[PY TD Market Share])=0,0,IF(SUM('NPD workflow'[PY Total Market Share])=0,0,SUM('NPD workflow'[PY TD Market Share])/SUM('NPD workflow'[PY Total Market Share])-1))

[Dimps]

Thank you!

[amitchandak]

@Dimps , Can you share sample data and sample output in table format? Or a sample pbix after removing sensitive data.

First refer if below can help

various ways to deal with this year last year

YTD Sales = CALCULATE(SUM(Sales[Sales Amount]),DATESYTD('Date'[Date],"12/31"))
Last YTD Sales = CALCULATE(SUM(Sales[Sales Amount]),DATESYTD(dateadd('Date'[Date],-1,Year),"12/31"))
This year Sales = CALCULATE(SUM(Sales[Sales Amount]),DATESYTD(ENDOFYEAR('Date'[Date]),"12/31"))
Last year Sales = CALCULATE(SUM(Sales[Sales Amount]),DATESYTD(ENDOFYEAR(dateadd('Date'[Date],-1,Year)),"12/31"))
Last to last YTD Sales = CALCULATE(SUM(Sales[Sales Amount]),DATESYTD(dateadd('Date'[Date],-2,Year),"12/31"))
Year behind Sales = CALCULATE(SUM(Sales[Sales Amount]),dateadd('Date'[Date],-1,Year))
Year behind Sales = CALCULATE(SUM(Sales[Sales Amount]),SAMEPERIODLASTYEAR('Date'[Date]))
last Year Sales = CALCULATE(SUM(Sales[Sales Amount]),previousyear('Date'[Date]))
Average PY = IF([Average CY]=0,BLANK(),CALCULATE([Average CY],SAMEPERIODLASTYEAR("dCalendar"[Date])))

//Only year vs Year, not a level below

This Year = CALCULATE(sum('Table'[Qty]),filter(ALL('Date'),'Date'[Year]=max('Date'[Year])))
Last Year = CALCULATE(sum('Table'[Qty]),filter(ALL('Date'),'Date'[Year]=max('Date'[Year])-1))

Power BI — Year on Year with or Without Time Intelligence
https://medium.com/@amitchandak.1978/power-bi-ytd-questions-time-intelligence-1-5-e3174b39f38a
https://www.youtube.com/watch?v=km41KfM_0uA