Finding Previous year's Sales in Power BI with week number

[Anonymous]

I am trying to find the Previous year sales for the same week in Power BI.I dont have any date column. I have two table .One is FACT Indicators table as shown below: 

and one sales table( Fact Sales table): 

I want to create one calculated field namely(Sales Previous Year) to show the previous year sales for the same week .

In 'Fact Indicators' table 'PY 52 week flag' filed shows if this week id is Previous year or not.

Week column shows the week number from 1 to 52 weeks .

Week Id shows the unique number per Market key.

'Market_Week Id Key' is the common joining key between FACT Indicators table and Fact Sales table

Please help me to find the formula for calculated field.

[amitchandak · Accepted solution]

@Anonymous , Week ID, Week and year move to an independent table (Say Date/week table)

Create a week rank on Week ID

Week Rank = RANKX(all('Date'),'Date'[Week ID],,ASC,Dense) //YYYYWW format

measures

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

same week last year

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

YTD

YTD= CALCULATE(sum('order'[Qty]), FILTER(ALL('Date'),'Date'[Year]=max('Date'[Year]) && 'Date'[Week] <= Max('Date'[Week]) ))
LYTD = CALCULATE(sum('order'[Qty]), FILTER(ALL('Date'),'Date'[Year]=max('Date'[Year])-1 && 'Date'[Week] <= Max('Date'[Week])))