Prior period comparison

Thanks for the reply from lbendlin , please allow me to provide another insight: 

Hi  Shawry ,

Here are the steps you can follow：

1. Create calculated column.

Past 6 Weeks or Prior Period =
var _today=TODAY()
var _weektoday=WEEKNUM(_today,2)
var _currentmaxdate=MAXX(FILTER(ALL('Table'),YEAR('Table'[Date])=YEAR(_today)&&'Table'[Week]=_weektoday-1),[Date])
var _currentmindate=MINX(FILTER(ALL('Table'),YEAR('Table'[Date])=YEAR(_today)&&'Table'[Week]=_weektoday-6),[Date])
var _lastmaxdate=MAXX(FILTER(ALL('Table'),YEAR('Table'[Date])=YEAR(_today)-1&&'Table'[Week]=_weektoday-1),[Date])
var _lastmindate=MINX(FILTER(ALL('Table'),YEAR('Table'[Date])=YEAR(_today)-1&&'Table'[Week]=_weektoday-6),[Date])
return
SWITCH(
    TRUE(),
    'Table'[Date]>=_currentmindate&&'Table'[Date]<=_currentmaxdate,"Last 6 weeks",
    'Table'[Date]>=_lastmindate&&'Table'[Date]<=_lastmaxdate,"Last 6 weeks prior period","False")

2. Result:

Best Regards,

Liu Yang

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