Building a slicer where each slice can contain the same data?

markmsc One method to make this work would be to create a separate table with no relationships that lists your slicer choices. Then, you could create a measure that returns 1 if a row of data is within the desired date range and 0 otherwise. You could then use this measure in a visual level filter and set it to only display rows/items where the measure is 1. Something like the following might work:

My Filter Measure = 
VAR _Days = 
  SWITCH( SELECTEDVALUE( 'Slicer'[Item] ),
    "Last 7 Days", 7,
    "Last 14 Days", 14,
    "Last 21 Days", 21,
    "Last 28 Days", 28,
  )
VAR _Date = MAX( 'Table'[Date] )
VAR _Result = IF( _Date <= TODAY() && _Date >= TODAY()-_Days, 1, 0 )
RETURN _Result

Great question!

1. Create a disconnected slicer table
   Create a small table with your choices. (No relationships needed.)
   
   Period =
   DATATABLE (
   "Label", STRING, "Days", INTEGER,
   {
   { "Last 7 days", 7 },
   { "Last 14 days", 14 },
   { "Last 21 days", 21 },
   { "Last 28 days", 28 }
   }
   )
   
   Use Period[Label] in a slicer. I recommend turning Single Select = On
   
   
2. Add a “Selected N” helper measure
   This reads the slicer. If nothing is chosen, it defaults to 7.
   Selected Days :=
   VAR N = MAX ( Period[Days] )
   RETURN IF ( NOT ISBLANK ( N ), N, 7 )
   
   
3. Choose the “as-of” date (respects your date slicer)
   This follows your preferred style (using MAXX with ALLSELECTED) so it anchors on the last selected date if a date slicer is present; otherwise it uses the max date in context.
   
   Selected Max Date :=
   MAXX ( ALLSELECTED ( 'Date'[Date] ), 'Date'[Date] )
   
   Replace 'Date'[Date] with your model’s primary date column. (No USERELATIONSHIP needed if your active relationship is already correct.)
   
   
   
4. Build a reusable date-window measure
   
   Is In Selected Period :=
   VAR N = [Selected Days]
   VAR MaxDate = [Selected Max Date]
   VAR StartDate = MaxDate - N + 1
   VAR CurrentDate = MAX ( 'Date'[Date] )
   RETURN
   IF ( CurrentDate >= StartDate && CurrentDate <= MaxDate, 1, 0 )
   
   
5. Filter visuals (easy, reusable way)
   
   Is In Selected Period :=
   VAR N = [Selected Days]
   VAR MaxDate = [Selected Max Date]
   VAR StartDate = MaxDate - N + 1
   VAR CurrentDate = MAX ( 'Date'[Date] )
   RETURN
   IF ( CurrentDate >= StartDate && CurrentDate <= MaxDate, 1, 0 )
   
   OR
   
   
6. Wrap your core measures
   
   Sales (Last N Days) :=
   VAR N = [Selected Days]
   VAR MaxDate = [Selected Max Date]
   RETURN
   CALCULATE (
   [Total Sales], -- your base measure
   DATESINPERIOD ( 'Date'[Date], MaxDate, -N, DAY ) -- rolling N-day window
   )
   
   Use this pattern for any measure (counts, distincts, amounts). DATESINPERIOD is efficient and readable.
   
   You’re done—an elegant “Last N days” slicer without messy buckets.