How can I subtract one date from another in the same column?

[Anonymous]

Here is a sample of what my data looks like in Power BI. I need to create a new column that subtracts the date from the previous row, and I need to do this for thousands of IDs. How can I accomplish this?

[Kishore_KVN]

First Create a Date Lookup Column and then create difference:

Dax for those two columns looks as below:

Date Lookup = LOOKUPVALUE('Dates Difference'[Dates],'Dates Difference'[Index],'Dates Difference'[Index]-1)

Dates Diff = DATEDIFF('Dates Difference'[Date Lookup],'Dates Difference'[Dates],DAY)

Result sample looks as below:

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[Greg_Deckler]

@Anonymous See my article on Mean Time Between Failure (MTBF) which uses EARLIER: http://community.powerbi.com/t5/Community-Blog/Mean-Time-Between-Failure-MTBF-and-Power-BI/ba-p/339586.
The basic pattern is:
Column = 
  VAR __Current = [Value]
  VAR __PreviousDate = MAXX(FILTER('Table','Table'[Date] < EARLIER('Table'[Date])),[Date])

  VAR __Previous = MAXX(FILTER('Table',[Date]=__PreviousDate),[Value])
RETURN
  __Current - __Previous