Same Week Last Year

Anonymous , Try with week Rank

new columns in date tbale

Week Start date = 'Date'[Date]+-1*WEEKDAY('Date'[Date],2)+1
Week End date = 'Date'[Date]+ 7-1*WEEKDAY('Date'[Date],2)
Week Number = WEEKNUM([Date],2)
Week = if('Date'[Week Number]<10,'Date'[Year]*10 & 'Date'[Week Number],'Date'[Year]&'Date'[Week Number])
Week Rank = RANKX(all('Date'),'Date'[Week Start date],,ASC,Dense)

 

Measure

 

This Week = CALCULATE(sum('order'[Qty]), FILTER(ALL('Date'),'Date'[Week Rank]=max('Date'[Week Rank])))
Last Week = CALCULATE(sum('order'[Qty]), FILTER(ALL('Date'),'Date'[Week Rank]=max('Date'[Week Rank])-1))
Last year Week= CALCULATE(sum('order'[Qty]), FILTER(ALL('Date'),'Date'[Week Rank]=(max('Date'[Week Rank]) -52)))

 

Refer by blog

https://community.powerbi.com/t5/Community-Blog/Week-Is-Not-So-Weak-WTD-Last-WTD-and-This-Week-vs-Last-Week/ba-p/1051123