Current vs Previous Period based on date selection in drop down, populate Table or Matrix Power BI

Hi sb4pbi 

Use a column from  a disconnected dates table for the dropdown as using one from the same or related table will show only that are selected from the slicer  - eg., if you select April 30, your visual will show this date only. Create one using DAX or M. Here's a sample DAX calc table.

DisconnectedDates = 
DISTINCT ( 'Data'[Date] )

Take note that there is no relationship between DisconnectedDates and Data in the screenshot below

Create the following measures

Current Week = 
VAR _RefDate =
    MAX ( DisconnectedDates[Date] )
VAR _start = _RefDate - 7
VAR _end = _RefDate - 1
RETURN
    CALCULATE (
        SUM ( Data[Value] ),
        KEEPFILTERS ( Data[Date] >= _start && Data[Date] <= _end )
    )

Previous Week = 
VAR _RefDate =
    MAX ( DisconnectedDates[Date] )
VAR _start = _RefDate - 14
VAR _end = _RefDate - 8
RETURN
    CALCULATE (
        SUM ( Data[Value] ),
        KEEPFILTERS ( Data[Date] >= _start && Data[Date] <= _end )
    )

 Create the following measure that can be used to sort a table with the current dates first then the previous ones.

Current or Prev = 
VAR _number =
    SWITCH (
        TRUE (),
        NOT ( ISBLANK ( [Current Week] ) ), 1,
        NOT ( ISBLANK ( [Previous Week] ) ), 2
    )
RETURN
    IF ( NOT ( ISBLANK ( _number ) ), REPT ( UNICHAR ( 8203 ), _number ) )

Rename this measure to a space once added to the table so the column name doesn't show. Resize it further so the arrow is not visible.

Please see the attached pbix.